CsTeamsFilesPolicy

If your organization chooses a third-party for content storage, you can turn off the NativeFileEntryPoints parameter in the Teams Files policy. This parameter is enabled by default, which shows option to attach OneDrive / SharePoint content from Teams chats or channels. When this parameter is disabled, users won't see access points for OneDrive and SharePoint in Teams. Please note that OneDrive app in the left navigation pane in Teams isn't affected by this policy. Teams administrators can also choose which file service will be used by default when users upload files from their local devices by dragging and dropping them in a chat or channel. OneDrive and SharePoint are the existing defaults, but admins can now change it to a third-party app. Teams administrators would be able to create a customized teams files policy to match the organization's requirements.