As the Xbox Series X name suggests, along with Halo Infinite already confirmed to be a Xbox One, Series and PC game.
For least the first year and maybe longer all Xbox Game Studio games will be available on all Xbox platforms.
You may have read post above about this as I did think this was implied ages ago that all Xbox Game Studio games would be on all the Xbox platforms, that I'm not sure if I'll get a Series X at launch because I can still play Halo Infinite for instance.
That's if I was normal but likely will as new technology plus can flog my One X etc
But does make the PS5 more appealing as semi been confirmed it will get games that are only on PS5.