[Update]: Microsoft has released a statement emphasising that only the Gears of War: Ultimate Edition of the Xbox One would include a free copy of the game. During the Comic-Con panel Rod Fergusson, head of Microsoft's Gear of War development studio, indicated that the game would be available for free with all Xbox Ones.
"At yesterday's Gears of War panel at San Diego Comic-Con, Rod Fergusson stated that every Xbox One sold starting August 26 would include a copy of Gears of War: Ultimate Edition. To clarify, only the Xbox One Gears of War: Ultimate Edition bundle will include a copy of the game," reads the statement.