In a recent interview, when asked about the future of the Gears of War franchise once the main trilogy is done and dusted, game director Cliff Bleszinski stated that the emergence of some form of spin-off or sequel would be “business 101.” Gears 1 and 2 sold about 6 million copies, so if [Gears of War 3] comes out and, God willing, sells 8 or 10 million it would be completely dumb to not do another one, right? Despite the series’ initial narrow approach towards narrative, over the past few years the Gears of War universe has continued to expand via print media, including a line of comic books and graphic novels which have played a part in influencing the series’ third installment. We wouldn’t be at all surprised to see Epic lead gamers into a fresh GoW story arc as soon as Delta’s draws to its much anticipated conclusion.
http://www.thesixthaxis.com/2011/07/19/gears-of-war-4-its-business-101/