TL;DR:
The Teams Video Clips feature was released late 2022. Microsoft is now adding auto-generated captions support. Now due July 2023.

Details:
This update is intended to close the accessibility gap for Teams Video Clips, but is also easier than grabbing your headphones to listen to a clip that’s just a few seconds long. The captions will be auto-generated once the video is uploaded, and you will be able to watch the Video Clip with auto-generated captions turned on.

The clip creator can download the captions/transcript and can only delete the captions by deleting the video clip.

Availability:
Due mid to late April 2023.
Now due early to mid-May 2023. 
Now due July 2023.

Source, related links, and references:
MC534735.

Page originally published:
13th April 2023 and kept up to date.