Halo Infinite doesn’t offer a cross-save between Steam on PC to Xbox console so you should take this in mind before playing the game on either platform.
The cross-save functionality only applies to the Xbox console or the Windows version of the game. If you own it on Steam, you won’t be able to transfer your save data between the two platforms.
This was verified by Tom Warren, Editor at The Verge. This is also similar to how Forza Horizon cross-save works where it is only applicable to the Windows version of the game.
I started playing Halo Infinite on Steam, and I have a campaign save there. I'm now trying to play on Xbox Series X and the campaign save isn't there. Looks like this is similar to Forza Horizon 5 where cross-save only works on the Windows Store PC version. Be warned 👇 pic.twitter.com/ACJovPuifZ
— Tom Warren (@tomwarren) December 8, 2021
Halo Infinite campaign has officially launched today on PC and Xbox consoles. The game is also available to play on the Xbox Game Pass. In addition to the campaign, there is a separate multiplayer mode that is free-to-play on both platforms.