It’s looking increasingly like Halo: The Master Chief Collection will land on PC soon. While we still don’t have a release date for Reach, 343 Industries has given us the Halo MCC system requirements and a big breakdown of the new progression system – as well as details on how cross-progression and cross-play will work.
Sadly, cross-play is going to be a bit limited. The Windows Store and Steam versions of the game will be fully compatible with each other, but Xbox One will be left out, at least at launch. “As we’ve said previously,” 343 notes in the full blog post, “this is something the team will monitor and evaluate over time.”
But cross-progression and cross-saves will be much more robust. Your campaign progress, playlist completion, career stats, medals, and account rank all update on your Xbox Live profile, and will stay with you on every platform. Any achievements you’ve unlocked on the Microsoft side will automatically unlock for Steam when sign in on Valve’s platform.
Original source: https://www.pcgamesn.com/halo-master-chief-collection/cross-platform