When it comes to game consoles, each had 2-3 exclusive franchises that were their signature. For Nintendo it's Mario, Zelda, and Pokemon. For Sony it's "Uncharted," "God of War," and "Infamous".
For Microsoft though it's all about "Halo" and "Gears of War". While MS owned the "Halo" franchise, 'Gears' was created by Epic Games and so there was always the possibility (however slim) of it eventually going multi-platform.
That is no longer the case. Microsoft Studios has now purchased the rights to all past and future "Gears of War" titles and the brand itself from Epic Games.
However, like with the "Halo" franchise since "Halo 4," the property is no longer being worked on by the company that created it. Epic's Unreal Engine 4 technology will be utilised for future installments though.
Instead, Microsoft have assigned Vancouver-based Black Tusk Studios to develop the next title in the co-op shooter series. Black Tusk has no finished games under its belt, but former 'Gears' executive producer Rod Fergusson is involved with the company.
The purchase also gives Microsoft the ability to pursue tie-in products from comics to a potential Xbox-exclusive TV series.