You can carry over your progress to and from PC and the Xbox One.
Halo: The Master Chief Collection, the now-impressive re-release and remastering the mainline Halo titles, is finally coming to PC. Though the beta was unfortunately delayed, it’s still on track to come out in full this year, and one big piece of news that was just revealed is that the game will have cross progression from PC to console, or vice versa- though cross-play is still up in the air.
The collection released on Xbox One in 2014 and included remastered versions of Halo: Combat Evolved, Halo 2, Halo 3, and Halo 4. Eventually, Halo 3: ODST was released to collection owners as well, while Halo Reach is being added in the future. Though the release was plagued with technical issues at launch, 343 has worked steadily on it to iron out most of the kinks. With the PC release, it’s also left many wondering how progression between the two versions will work. Halo Community Director Brian Jarrard answered the question via his Twitter account, which you can see below, to confirm that cross progression between PC and console will definitely be a thing. On the other hhand, though, it seems that cross-play isn’t in for sure yet, though Jarrard says it’s being evaluated.
Halo: The Master Chief Collection is out now for Xbox One and will come out on PC (including Steam) at an as of yet undetermined time- but Microsoft is aiming to get it out at by the end of the year. When it does release there, it will make Halo 5 the last Halo title to not have a PC release.
Progression, unlocks, stats, etc.. will carry over between PC/console. In terms of playing together crossplatform, currently not planned for launch but it's something the team is accounting for and will evaluate over time.
— Brian Jarrard (@ske7ch) May 2, 2019