Apple has seeded the first release candidate of tvOS 17.5 to developers for testing. The build number is 21L569.
The update follows the release oftvOS 17.4, tvOS 17.3 and tvOS 17.2 which enhanced the FaceTime, Fitness, and Apple TV apps, streamlined voice search in supported apps, added new support for Siri, and included performance and stability improvements.
Note that Apple typically doesn't reveal what's new in tvOS until final release.