At the moment, the only way to play Halo 5: Guardians is on Xbox One console. However, the franchise director for the Halo series, Microsoft's Frank O'Conner, offered new hope that the first person shooter could be released at some point for the PC, and most likely as a Windows 10 exclusive game.
In a Twitch.tv Halo 5 session hosted by GamesRadar, O'Connor was asked about Halo 5 showing up on the PC:
"You know, Microsoft has made a huge commitment trying sort of… I think normalize the Windows experience across multiple platforms. You see the elements of Windows 10 are going to appear in Xbox and Cortana and stuff like that. There is plenty of chance that Halo 5 could appear on the PC. Nothing to announce at this point… you know, we developed the game on an Intel platform. It wouldn't be the hardest thing in the world to move it to PC and take advantage of PC stuff. But nothing I announce today on this chat."
Whatever happens with Halo 5 on the PC, we do know that Microsoft plans to release the RTS game Halo Wars 2 for both the Xbox One and Windows 10 sometime in the fall of 2016.