Halo: Spartan Assault was released by Microsoft Studios in July of this year. The third-person shooter was developed by 343 Industries in sight of touch-enabled devices and hence was only released for Windows 8 and Windows Phone.
Today however that exclusivity ends with Microsoft announcing that the game would finally be releasing for the Xbox 360 and Xbox One later this year in December. The announcement also mentioned that the console versions would feature a new online co-op mode, as well as new missions, weapons, armor abilities, upgrades and the Operation Hydra expansion for players. Besides the said aspects though, the game will pretty much remain the same.
Halo: Spartan Assault takes place between the events of Halo 3 and Halo 4 and offers more background story to the human-Covenant conflict; for which the UNSC and Covenant signed a ceasefire in Halo 3.
Halo: Spartan Assault is going to be sold separately for both consoles. If you end up buying it for the Xbox 360, you’ll have to purchase it ‘again’ for the Xbox One in the future.
Source: Halo Waypoint