Tom’s Guide revealed that the tvOS 16.5 Beta now has a multi-view sports feature.

Multi-view is similar to Picture-in-Picture mode but allows up to four different ‘windows’ or sports games in a four-quarter screen layout simultaneously. Users should be able to control which game they want the audio on via the Siri remote. It’s available on MLB Friday Night Baseball and the MLS Season Pass once it goes live on April 15.
Apple TV users can enable multi-view by choosing the grid icon located above the timeline, then choosing ‘More Matches’. The first sighting of multi-view was discovered last month by Steve Moser although the code for it was hidden. Another caveat is that multi-view is only available via the TV app and therefore limited to the MLS and MLB for now. Apple has yet to announce the feature since it’s currently in the beta stage, but the public version might be released in the coming month.