Users can tap the camera icon to turn the camera on and off, and can tap the letter V to select another camera.
Tapping the V next to the camera icon brings up a camera selection dialogue with a live preview. When the user selects another camera, that camera will be selected and the user can tap anywhere outside of the conversation to dismiss the conversation.
Device administrators can select the default video camera by selecting it from the device settings, through XML configuration, or from the group admin center user interface.
If the device does not have multiple USB cameras set up with the Team Room device in the meeting rooms, there will be no difference in the experience.
This update only for Microsoft Teams Rooms for Windows is expected to be available mid-December in the Microsoft store.
https://mspoweruser.com/microsoft-teams-rooms-is-getting-better-multi-camera-support/ Microsoft Teams rooms are getting better camera support