Do you mean that you want to add an app in Teams?
If so, you can add apps in tabs in both chats and channels. For more information, please read the following articles:
- https://support.microsoft.com/en-us/office/add-an-app-to-microsoft-teams-b2217706-f7ed-4e64-8e96-c413afd02f77
- https://support.microsoft.com/en-us/office/five-things-to-know-about-apps-in-microsoft-teams-747492ee-7cdd-4115-a993-8c7e7f98a3d0
If you want to deploy other applications, it seems no direct ways to realize by Teams.
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