diff --git a/pyproject.toml b/pyproject.toml
index 989e63122f640..8187bbd3507c8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -59,7 +59,6 @@ module = [
     "pytorch_lightning.demos.boring_classes",
     "pytorch_lightning.demos.mnist_datamodule",
     "pytorch_lightning.loggers.comet",
-    "pytorch_lightning.loggers.mlflow",
     "pytorch_lightning.loggers.neptune",
     "pytorch_lightning.loggers.tensorboard",
     "pytorch_lightning.loggers.wandb",
diff --git a/src/pytorch_lightning/loggers/logger.py b/src/pytorch_lightning/loggers/logger.py
index 03d934aa58760..56bf4660c29dd 100644
--- a/src/pytorch_lightning/loggers/logger.py
+++ b/src/pytorch_lightning/loggers/logger.py
@@ -203,12 +203,12 @@ def group_separator(self) -> str:
 
     @property
     @abstractmethod
-    def name(self) -> str:
+    def name(self) -> Optional[str]:
         """Return the experiment name."""
 
     @property
     @abstractmethod
-    def version(self) -> Union[int, str]:
+    def version(self) -> Optional[Union[int, str]]:
         """Return the experiment version."""
 
 
diff --git a/src/pytorch_lightning/loggers/mlflow.py b/src/pytorch_lightning/loggers/mlflow.py
index b8ce0ef423a31..313fcfe07f10e 100644
--- a/src/pytorch_lightning/loggers/mlflow.py
+++ b/src/pytorch_lightning/loggers/mlflow.py
@@ -50,7 +50,17 @@
     from mlflow.tracking.context.registry import resolve_tags
 else:
 
-    def resolve_tags(tags=None):
+    def resolve_tags(tags: Optional[Dict] = None) -> Optional[Dict]:
+        """
+        Args:
+            tags: A dictionary of tags to override. If specified, tags passed in this argument will
+                 override those inferred from the context.
+
+        Returns: A dictionary of resolved tags.
+
+        Note:
+            See ``mlflow.tracking.context.registry`` for more details.
+        """
         return tags
 
 
@@ -129,7 +139,7 @@ def __init__(
             tracking_uri = f"{LOCAL_FILE_URI_PREFIX}{save_dir}"
 
         self._experiment_name = experiment_name
-        self._experiment_id = None
+        self._experiment_id: Optional[str] = None
         self._tracking_uri = tracking_uri
         self._run_name = run_name
         self._run_id = run_id
@@ -141,7 +151,7 @@ def __init__(
 
         self._mlflow_client = MlflowClient(tracking_uri)
 
-    @property
+    @property  # type: ignore[misc]
     @rank_zero_experiment
     def experiment(self) -> MlflowClient:
         r"""
@@ -187,7 +197,7 @@ def experiment(self) -> MlflowClient:
         return self._mlflow_client
 
     @property
-    def run_id(self) -> str:
+    def run_id(self) -> Optional[str]:
         """Create the experiment if it does not exist to get the run id.
 
         Returns:
@@ -197,7 +207,7 @@ def run_id(self) -> str:
         return self._run_id
 
     @property
-    def experiment_id(self) -> str:
+    def experiment_id(self) -> Optional[str]:
         """Create the experiment if it does not exist to get the experiment id.
 
         Returns:
@@ -261,7 +271,7 @@ def save_dir(self) -> Optional[str]:
             return self._tracking_uri.lstrip(LOCAL_FILE_URI_PREFIX)
 
     @property
-    def name(self) -> str:
+    def name(self) -> Optional[str]:
         """Get the experiment id.
 
         Returns:
@@ -270,7 +280,7 @@ def name(self) -> str:
         return self.experiment_id
 
     @property
-    def version(self) -> str:
+    def version(self) -> Optional[str]:
         """Get the run id.
 
         Returns: