diff --git a/.flake8 b/.flake8
index 8f3b4fd4..60d7ac9b 100644
--- a/.flake8
+++ b/.flake8
@@ -1,3 +1,4 @@
+
 [flake8]
 extend-select =
     # bugbear
@@ -22,4 +23,4 @@ extend-ignore =
 max-line-length = 80
 per-file-ignores =
     # __init__ exports names
-    src/flask/__init__.py: F401
+    src/flask/__init__.py: F401
\ No newline at end of file
diff --git a/.github/workflows/lock.yaml b/.github/workflows/lock.yaml
index c790fae5..05d0b273 100644
--- a/.github/workflows/lock.yaml
+++ b/.github/workflows/lock.yaml
@@ -22,4 +22,4 @@ jobs:
       - uses: dessant/lock-threads@c1b35aecc5cdb1a34539d14196df55838bb2f836
         with:
           issue-inactive-days: 14
-          pr-inactive-days: 14
+          pr-inactive-days: 14
\ No newline at end of file
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 79a56fca..65b9877d 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -52,7 +52,7 @@ jobs:
         uses: actions/cache@58c146cc91c5b9e778e71775dfe9bf1442ad9a12
         with:
           path: ./.mypy_cache
-          key: mypy|${{ matrix.python }}|${{ hashFiles('setup.cfg') }}
+          key: mypy|${{ matrix.python }}|${{ hashFiles('pyproject.toml') }}
         if: matrix.tox == 'typing'
       - run: pip install tox
       - run: tox run -e ${{ matrix.tox }}
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 2b1dee57..d56c3451 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,5 +1,5 @@
 ci:
-  autoupdate_branch: "2.1.x"
+  autoupdate_branch: "2.2.x"
   autoupdate_schedule: monthly
 repos:
   - repo: https://github.com/asottile/pyupgrade
diff --git a/CHANGES.rst b/CHANGES.rst
index 79e66e95..94c16a34 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,13 @@
+Version 2.3.0
+-------------
+
+Unreleased
+
+-   Use modern packaging metadata with ``pyproject.toml`` instead of ``setup.cfg``.
+    :pr:`4947`
+-   Ensure subdomains are applied with nested blueprints. :issue:`4834`
+
+
 Version 2.2.3
 -------------
 
diff --git a/docs/blueprints.rst b/docs/blueprints.rst
index af368bac..d5cf3d82 100644
--- a/docs/blueprints.rst
+++ b/docs/blueprints.rst
@@ -140,6 +140,19 @@ name, and child URLs will be prefixed with the parent's URL prefix.
     url_for('parent.child.create')
     /parent/child/create
 
+In addition a child blueprint's will gain their parent's subdomain,
+with their subdomain as prefix if present i.e.
+
+.. code-block:: python
+
+    parent = Blueprint('parent', __name__, subdomain='parent')
+    child = Blueprint('child', __name__, subdomain='child')
+    parent.register_blueprint(child)
+    app.register_blueprint(parent)
+
+    url_for('parent.child.create', _external=True)
+    "child.parent.domain.tld"
+
 Blueprint-specific before request functions, etc. registered with the
 parent will trigger for the child. If a child does not have an error
 handler that can handle a given exception, the parent's will be tried.
diff --git a/docs/cli.rst b/docs/cli.rst
index 22484f17..a3ea268e 100644
--- a/docs/cli.rst
+++ b/docs/cli.rst
@@ -95,7 +95,7 @@ the ``--debug`` option.
 
 .. code-block:: console
 
-     $ flask --app hello --debug run
+     $ flask --app hello run --debug
       * Serving Flask app "hello"
       * Debug mode: on
       * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
@@ -550,7 +550,7 @@ a name such as "flask run".
 Click the *Script path* dropdown and change it to *Module name*, then input ``flask``.
 
 The *Parameters* field is set to the CLI command to execute along with any arguments.
-This example uses ``--app hello --debug run``, which will run the development server in
+This example uses ``--app hello run --debug``, which will run the development server in
 debug mode. ``--app hello`` should be the import or file with your Flask app.
 
 If you installed your project as a package in your virtualenv, you may uncheck the
diff --git a/docs/config.rst b/docs/config.rst
index 7cffc44b..9446e456 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -47,12 +47,12 @@ Debug Mode
 
 The :data:`DEBUG` config value is special because it may behave inconsistently if
 changed after the app has begun setting up. In order to set debug mode reliably, use the
-``--debug`` option on the ``flask`` command. ``flask run`` will use the interactive
+``--debug`` option on the ``flask run`` command. ``flask run`` will use the interactive
 debugger and reloader by default in debug mode.
 
 .. code-block:: text
 
-    $ flask --app hello --debug run
+    $ flask --app hello run --debug
 
 Using the option is recommended. While it is possible to set :data:`DEBUG` in your
 config or code, this is strongly discouraged. It can't be read early by the ``flask run``
diff --git a/docs/debugging.rst b/docs/debugging.rst
index fb3604b0..18f42867 100644
--- a/docs/debugging.rst
+++ b/docs/debugging.rst
@@ -43,7 +43,7 @@ The debugger is enabled by default when the development server is run in debug m
 
 .. code-block:: text
 
-    $ flask --app hello --debug run
+    $ flask --app hello run --debug
 
 When running from Python code, passing ``debug=True`` enables debug mode, which is
 mostly equivalent.
@@ -72,7 +72,7 @@ which can interfere.
 
 .. code-block:: text
 
-    $ flask --app hello --debug run --no-debugger --no-reload
+    $ flask --app hello run --debug --no-debugger --no-reload
 
 When running from Python:
 
diff --git a/docs/quickstart.rst b/docs/quickstart.rst
index 02dbc978..0d7ad3f6 100644
--- a/docs/quickstart.rst
+++ b/docs/quickstart.rst
@@ -108,7 +108,7 @@ To enable debug mode, use the ``--debug`` option.
 
 .. code-block:: text
 
-    $ flask --app hello --debug run
+    $ flask --app hello run --debug
      * Serving Flask app 'hello'
      * Debug mode: on
      * Running on http://127.0.0.1:5000 (Press CTRL+C to quit)
@@ -359,7 +359,7 @@ the application secure.  Because of that Flask configures the `Jinja2
 
 Templates can be used to generate any type of text file. For web applications, you'll
 primarily be generating HTML pages, but you can also generate markdown, plain text for
-emails, any anything else.
+emails, and anything else.
 
 For a reference to HTML, CSS, and other web APIs, use the `MDN Web Docs`_.
 
diff --git a/docs/server.rst b/docs/server.rst
index a34dfab5..d38aa120 100644
--- a/docs/server.rst
+++ b/docs/server.rst
@@ -24,7 +24,7 @@ debug mode.
 
 .. code-block:: text
 
-    $ flask --app hello --debug run
+    $ flask --app hello run --debug
 
 This enables debug mode, including the interactive debugger and reloader, and then
 starts the server on http://localhost:5000/. Use ``flask run --help`` to see the
diff --git a/docs/tutorial/factory.rst b/docs/tutorial/factory.rst
index c8e2c5f4..39febd13 100644
--- a/docs/tutorial/factory.rst
+++ b/docs/tutorial/factory.rst
@@ -137,7 +137,7 @@ follow the tutorial.
 
 .. code-block:: text
 
-    $ flask --app flaskr --debug run
+    $ flask --app flaskr run --debug
 
 You'll see output similar to this:
 
diff --git a/docs/views.rst b/docs/views.rst
index 8937d7b5..f2210270 100644
--- a/docs/views.rst
+++ b/docs/views.rst
@@ -249,7 +249,7 @@ provide get (list) and post (create) methods.
         init_every_request = False
 
         def __init__(self, model):
-            self.model
+            self.model = model
             self.validator = generate_validator(model)
 
         def _get_item(self, id):
@@ -297,7 +297,7 @@ provide get (list) and post (create) methods.
             db.session.commit()
             return jsonify(item.to_json())
 
-    def register_api(app, model, url):
+    def register_api(app, model, name):
         item = ItemAPI.as_view(f"{name}-item", model)
         group = GroupAPI.as_view(f"{name}-group", model)
         app.add_url_rule(f"/{name}/<int:id>", view_func=item)
diff --git a/examples/tutorial/README.rst b/examples/tutorial/README.rst
index a7e12ca2..1c745078 100644
--- a/examples/tutorial/README.rst
+++ b/examples/tutorial/README.rst
@@ -48,7 +48,7 @@ Run
 .. code-block:: text
 
     $ flask --app flaskr init-db
-    $ flask --app flaskr --debug run
+    $ flask --app flaskr run --debug
 
 Open http://127.0.0.1:5000 in a browser.
 
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..95a6e100
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,94 @@
+[project]
+name = "Flask"
+description = "A simple framework for building complex web applications."
+readme = "README.rst"
+license = {text = "BSD-3-Clause"}
+maintainers = [{name = "Pallets", email = "contact@palletsprojects.com"}]
+authors = [{name = "Armin Ronacher", email = "armin.ronacher@active-4.com"}]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Environment :: Web Environment",
+    "Framework :: Flask",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: BSD License",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python",
+    "Topic :: Internet :: WWW/HTTP :: Dynamic Content",
+    "Topic :: Internet :: WWW/HTTP :: WSGI",
+    "Topic :: Internet :: WWW/HTTP :: WSGI :: Application",
+    "Topic :: Software Development :: Libraries :: Application Frameworks",
+]
+requires-python = ">=3.7"
+dependencies = [
+    "Werkzeug>=2.2.2",
+    "Jinja2>=3.0",
+    "itsdangerous>=2.0",
+    "click>=8.0",
+    "importlib-metadata>=3.6.0; python_version < '3.10'",
+]
+dynamic = ["version"]
+
+[project.urls]
+Donate = "https://palletsprojects.com/donate"
+Documentation = "https://flask.palletsprojects.com/"
+Changes = "https://flask.palletsprojects.com/changes/"
+"Source Code" = "https://github.com/pallets/flask/"
+"Issue Tracker" = "https://github.com/pallets/flask/issues/"
+Twitter = "https://twitter.com/PalletsTeam"
+Chat = "https://discord.gg/pallets"
+
+[project.optional-dependencies]
+async = ["asgiref>=3.2"]
+dotenv = ["python-dotenv"]
+
+[project.scripts]
+flask = "flask.cli:main"
+
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools.dynamic]
+version = {attr = "flask.__version__"}
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+filterwarnings = ["error"]
+
+[tool.coverage.run]
+branch = true
+source = ["flask", "tests"]
+
+[tool.coverage.paths]
+source = ["src", "*/site-packages"]
+
+[tool.mypy]
+python_version = "3.7"
+files = ["src/flask"]
+show_error_codes = true
+pretty = true
+#strict = true
+allow_redefinition = true
+disallow_subclassing_any = true
+#disallow_untyped_calls = true
+#disallow_untyped_defs = true
+#disallow_incomplete_defs = true
+no_implicit_optional = true
+local_partial_types = true
+#no_implicit_reexport = true
+strict_equality = true
+warn_redundant_casts = true
+warn_unused_configs = true
+warn_unused_ignores = true
+#warn_return_any = true
+#warn_unreachable = true
+
+[[tool.mypy.overrides]]
+module = [
+    "asgiref.*",
+    "blinker.*",
+    "dotenv.*",
+    "cryptography.*",
+    "importlib_metadata",
+]
+ignore_missing_imports = true
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 736bd50f..00000000
--- a/setup.cfg
+++ /dev/null
@@ -1,96 +0,0 @@
-[metadata]
-name = Flask
-version = attr: flask.__version__
-url = https://palletsprojects.com/p/flask
-project_urls =
-    Donate = https://palletsprojects.com/donate
-    Documentation = https://flask.palletsprojects.com/
-    Changes = https://flask.palletsprojects.com/changes/
-    Source Code = https://github.com/pallets/flask/
-    Issue Tracker = https://github.com/pallets/flask/issues/
-    Twitter = https://twitter.com/PalletsTeam
-    Chat = https://discord.gg/pallets
-license = BSD-3-Clause
-author = Armin Ronacher
-author_email = armin.ronacher@active-4.com
-maintainer = Pallets
-maintainer_email = contact@palletsprojects.com
-description = A simple framework for building complex web applications.
-long_description = file: README.rst
-long_description_content_type = text/x-rst
-classifiers =
-    Development Status :: 5 - Production/Stable
-    Environment :: Web Environment
-    Framework :: Flask
-    Intended Audience :: Developers
-    License :: OSI Approved :: BSD License
-    Operating System :: OS Independent
-    Programming Language :: Python
-    Topic :: Internet :: WWW/HTTP :: Dynamic Content
-    Topic :: Internet :: WWW/HTTP :: WSGI
-    Topic :: Internet :: WWW/HTTP :: WSGI :: Application
-    Topic :: Software Development :: Libraries :: Application Frameworks
-
-[options]
-packages = find:
-package_dir = = src
-include_package_data = True
-python_requires = >= 3.7
-# Dependencies are in setup.py for GitHub's dependency graph.
-
-[options.packages.find]
-where = src
-
-[options.entry_points]
-console_scripts =
-    flask = flask.cli:main
-
-[tool:pytest]
-testpaths = tests
-filterwarnings =
-    error
-
-[coverage:run]
-branch = True
-source =
-    flask
-    tests
-
-[coverage:paths]
-source =
-    src
-    */site-packages
-
-[mypy]
-files = src/flask, tests/typing
-python_version = 3.7
-show_error_codes = True
-allow_redefinition = True
-disallow_subclassing_any = True
-# disallow_untyped_calls = True
-# disallow_untyped_defs = True
-# disallow_incomplete_defs = True
-no_implicit_optional = True
-local_partial_types = True
-# no_implicit_reexport = True
-strict_equality = True
-warn_redundant_casts = True
-warn_unused_configs = True
-warn_unused_ignores = True
-# warn_return_any = True
-# warn_unreachable = True
-
-[mypy-asgiref.*]
-ignore_missing_imports = True
-
-[mypy-blinker.*]
-ignore_missing_imports = True
-
-[mypy-dotenv.*]
-ignore_missing_imports = True
-
-[mypy-cryptography.*]
-ignore_missing_imports = True
-
-[mypy-importlib_metadata]
-ignore_missing_imports = True
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 67175467..00000000
--- a/setup.py
+++ /dev/null
@@ -1,17 +0,0 @@
-from setuptools import setup
-
-# Metadata goes in setup.cfg. These are here for GitHub's dependency graph.
-setup(
-    name="Flask",
-    install_requires=[
-        "Werkzeug >= 2.2.2",
-        "Jinja2 >= 3.0",
-        "itsdangerous >= 2.0",
-        "click >= 8.0",
-        "importlib-metadata >= 3.6.0; python_version < '3.10'",
-    ],
-    extras_require={
-        "async": ["asgiref >= 3.2"],
-        "dotenv": ["python-dotenv"],
-    },
-)
diff --git a/src/flask/__init__.py b/src/flask/__init__.py
index 4bd52311..185a465a 100644
--- a/src/flask/__init__.py
+++ b/src/flask/__init__.py
@@ -42,7 +42,7 @@ from .templating import render_template_string as render_template_string
 from .templating import stream_template as stream_template
 from .templating import stream_template_string as stream_template_string
 
-__version__ = "2.2.3.dev"
+__version__ = "2.3.0.dev"
 
 
 def __getattr__(name):
diff --git a/src/flask/app.py b/src/flask/app.py
index 0ac4bbb5..315cb6b1 100644
--- a/src/flask/app.py
+++ b/src/flask/app.py
@@ -2451,7 +2451,7 @@ class Flask(Scaffold):
         :data:`request` point at the request for the created
         environment. ::
 
-            with test_request_context(...):
+            with app.test_request_context(...):
                 generate_report()
 
         When using the shell, it may be easier to push and pop the
diff --git a/src/flask/blueprints.py b/src/flask/blueprints.py
index f6d62ba8..2403be1c 100644
--- a/src/flask/blueprints.py
+++ b/src/flask/blueprints.py
@@ -358,6 +358,9 @@ class Blueprint(Scaffold):
         :param options: Keyword arguments forwarded from
             :meth:`~Flask.register_blueprint`.
 
+        .. versionchanged:: 2.3
+            Nested blueprints now correctly apply subdomains.
+
         .. versionchanged:: 2.0.1
             Nested blueprints are registered with their dotted name.
             This allows different blueprints with the same name to be
@@ -453,6 +456,17 @@ class Blueprint(Scaffold):
         for blueprint, bp_options in self._blueprints:
             bp_options = bp_options.copy()
             bp_url_prefix = bp_options.get("url_prefix")
+            bp_subdomain = bp_options.get("subdomain")
+
+            if bp_subdomain is None:
+                bp_subdomain = blueprint.subdomain
+
+            if state.subdomain is not None and bp_subdomain is not None:
+                bp_options["subdomain"] = bp_subdomain + "." + state.subdomain
+            elif bp_subdomain is not None:
+                bp_options["subdomain"] = bp_subdomain
+            elif state.subdomain is not None:
+                bp_options["subdomain"] = state.subdomain
 
             if bp_url_prefix is None:
                 bp_url_prefix = blueprint.url_prefix
diff --git a/tests/test_blueprints.py b/tests/test_blueprints.py
index 1bf130f5..dbe00b97 100644
--- a/tests/test_blueprints.py
+++ b/tests/test_blueprints.py
@@ -950,6 +950,55 @@ def test_nesting_url_prefixes(
     assert response.status_code == 200
 
 
+def test_nesting_subdomains(app, client) -> None:
+    subdomain = "api"
+    parent = flask.Blueprint("parent", __name__)
+    child = flask.Blueprint("child", __name__)
+
+    @child.route("/child/")
+    def index():
+        return "child"
+
+    parent.register_blueprint(child)
+    app.register_blueprint(parent, subdomain=subdomain)
+
+    client.allow_subdomain_redirects = True
+
+    domain_name = "domain.tld"
+    app.config["SERVER_NAME"] = domain_name
+    response = client.get("/child/", base_url="http://api." + domain_name)
+
+    assert response.status_code == 200
+
+
+def test_child_and_parent_subdomain(app, client) -> None:
+    child_subdomain = "api"
+    parent_subdomain = "parent"
+    parent = flask.Blueprint("parent", __name__)
+    child = flask.Blueprint("child", __name__, subdomain=child_subdomain)
+
+    @child.route("/")
+    def index():
+        return "child"
+
+    parent.register_blueprint(child)
+    app.register_blueprint(parent, subdomain=parent_subdomain)
+
+    client.allow_subdomain_redirects = True
+
+    domain_name = "domain.tld"
+    app.config["SERVER_NAME"] = domain_name
+    response = client.get(
+        "/", base_url=f"http://{child_subdomain}.{parent_subdomain}.{domain_name}"
+    )
+
+    assert response.status_code == 200
+
+    response = client.get("/", base_url=f"http://{parent_subdomain}.{domain_name}")
+
+    assert response.status_code == 404
+
+
 def test_unique_blueprint_names(app, client) -> None:
     bp = flask.Blueprint("bp", __name__)
     bp2 = flask.Blueprint("bp", __name__)