Gears of War 3 will have at least 4 DLC packs within 1 year of the game’s release. This is known from the Season Pass announcement, which gives players the chance to buy all four DLC packs for 33% off, by paying 2400 Microsoft Points up front. The first DLC pack is scheduled to be released in November.
Cliff Bleszinski has said that there will both multi-player and single-player content. When speaking about the campaign oriented content, Cliff said it “won't be the graphic novel, but it will have all new campaign content that doesn't have Marcus, Dom, Cole and Baird in it. Expect Barrick and more.” Barrick is a character in the Gears of War graphic novels.
A clever gamer also found 3 non-playable maps in the online leaderboards for Gears of War 3. Whether the maps, “Azura,” “Blood Drive,” and “Rustlung” are future additions or maps that just didn’t make the cut remains to be seen. These maps can be seen on the leaderboards, which is evidenced in the video embedded on this page.