Earlier in the day, Apple released an update to its App Store guidelines, including some changes in its regulations regarding game streaming. Previously, the App Store did not allow game streaming services like Google Stadia, Microsoft xCloud, and Nvidia GeForce Now because Apple claimed that it cannot review each game being made available via the service.
With the recent changes in the guidelines, game streaming services are now allowed... as long as publishers submit each game for Apple's approval separately. Microsoft has now cited concerns with Apple's strategy, and hasn't taken kindly to the Cupertino tech giant's "olive branch".
In a statement to The Verge, Microsoft explained that:
This remains a bad experience for customers. Gamers want to jump directly into a game from their curated catalog within one app just like they do with movies or songs, and not be forced to download over 100 apps to play individual games from the cloud. We’re committed to putting gamers at the center of everything we do, and providing a great experience is core to that mission.
Microsoft's concerns do appear to be valid since the core experience of game streaming involves ideally having all games in one place and being able to switch from one title to the other without breaking immersion too much. While Apple does allow publishers a "catalog" app to list all their games in one place, accessing them would still require interaction with their respective App Store listings, an experience Microsoft obviously does not prefer.
Another caveat in Apple's guidelines is that developers will have to allow users to sign up for the service in the app, meaning that Apple gets a 30% cut, and they'll have to support the "Sign in with Apple". This is already something Epic Games is battling against the Cupertino firm in courts, and while Microsoft hasn't publicly cited concerns against the pricing model in this case, it would definitely strengthen Epic Games' case if the Redmond giant decides to take this to court as well.
Source: The Verge