Rockstar San Diego's Next Game – IGN News

Rockstar San Diego, the studio that brought you last generation’s hit open-world action game Red Dead Redemption, is working on a new title that will apparently feature “dynamic multiplayer” integrated within “all areas of gameplay.”

Read more here:
http://www.ign.com/articles/2015/05/22/red-dead-redemption-devs-next-game-will-feature-dynamic-multiplayer