Recently at the Game Developers Conference, Microsoft made an announcement stating that there will be cross-buy support for games on Windows 10 and Xbox One. The cross-buy feature will work similar to the Playstation system's cross-buy. Some games you purchase on the Xbox One will work on Windows 10 and vice-versa. If you own games supported on Windows 10 on the Xbox One right now, you will have access to it when you get Windows 10 as well. The cross-buy support is coming as part of Microsoft's Windows Universal App Platform, which allows the same version of a game to be run on all Windows devices, although Microsoft didn't make clear how many games will have the cross-buy support, and how common it will be. As of right now, the decision on if a game has the cross-buy support is fully in the hands of the game developer, and Microsoft isn't making the feature mandatory.
