They (Microsoft) are finally pushing cross-platform play and some sales. So this game will probably be playable against PC & Xbox players.
MS is trying to put Xbox on PC, again, G4WL was their last attempt at this. Its way overdue. There are plenty of negatives but overall its a good thing, I would expect many older XBox titles to be sold on the MS store over the next few years. Consoles are PCs, MS has always known this, their plan has always been to invade the living room with a some type of PC.
One issue is the format the games are released in, UWP instead of EXE, this means no mods and most apps do not work with them, even the folder the apps reside in is locked down for the average user. Forced options like no way to turn off V-Sync...MS really loves PC gaming so much, so much they want to control every aspect of it thus taking away freedom from the user thus they don't have a clue. If they would just release all their games on Steam, but no, they want to leverage the store into a position where you have to use it, just look at what happened to Solitaire.
EDIT:
New announcement related to cross-platform play
Microsoft has announced it will natively support cross-platform play between Xbox One, Windows 10, and other "online multiplayer networks." The move effectively opens the Xbox Live platform so that it can accommodate players on Sony's PlayStation Network, among others.