Microsoft and 343 announced about two weeks ago that there was a huge announcement regarding Halo: MCC. There was already a Surface Hub picture showing the the Halo: MCC cover art. But than we have CRYPTIC tweet.
https://www.reddit.com/r/halo/comments/b...udios_rep/
Update: It is coming to Steam.
https://store.steampowered.com/app/97673...ollection/