"Xbox Game Pass is headed to PC, with support from top publishers like Bethesda, Sega, Devolver, Paradox and Deep Silver.
As with the Xbox One version of Xbox Game Pass (the two are named the same, but will remain separate), all Microsoft exclusives will launch day and date into the program on their global release.
There will also be a library of 100+ games to dip into. (On Xbox One, this figure is now well over 200.) There's no word yet on pricing or specific games, but Microsoft says it's working with 75 PC developers and publishers, including the big names listed above...."
MS also mentions in the article about having their games available on multiple store fronts like; Steam, Epic, and Windows store.