diff --git a/third_party/2and3/requests/sessions.pyi b/third_party/2and3/requests/sessions.pyi
index 33c7b79e1..db275ae4e 100644
--- a/third_party/2and3/requests/sessions.pyi
+++ b/third_party/2and3/requests/sessions.pyi
@@ -62,7 +62,7 @@ _HooksInput = MutableMapping[Text, Union[Iterable[_Hook], _Hook]]
 
 class Session(SessionRedirectMixin):
     __attrs__: Any
-    headers: MutableMapping[Text, Text]
+    headers: CaseInsensitiveDict[Text]
     auth: Union[None, Tuple[Text, Text], _auth.AuthBase, Callable[[Request], Request]]
     proxies: MutableMapping[Text, Text]
     hooks: _Hooks
diff --git a/third_party/2and3/requests/structures.pyi b/third_party/2and3/requests/structures.pyi
index 92cf27aa1..807f39a1c 100644
--- a/third_party/2and3/requests/structures.pyi
+++ b/third_party/2and3/requests/structures.pyi
@@ -10,6 +10,7 @@ class CaseInsensitiveDict(MutableMapping[str, _VT], Generic[_VT]):
     def __delitem__(self, key: str) -> None: ...
     def __iter__(self) -> Iterator[str]: ...
     def __len__(self) -> int: ...
+    def copy(self) -> CaseInsensitiveDict: ...
 
 class LookupDict(Dict[str, _VT]):
     name: Any