TL;DR:
You will soon be able to preview and play Stream videos directly in Microsoft Teams Chats and Channels without having to open them in a browser and going to Stream. Now due by late October 2023.

Details:
Microsoft: “Stream videos that are saved in OneDrive and SharePoint are now embedded in chat and channels enabling users to preview and play them directly in Teams without the need to open a browser window”.


Availability:
Due late July to late August 2023.
Now due by late October 2023.

Source, related links, and references:
MC649917.
365 Roadmap ID 127596.

Page originally published:
21st July 2023 and kept up to date.

Want to know what else is late, new and coming soon across M365 and Teams this month? Check out the latest roundup.