It appears that Don Cheadle will return to the Marvel Universe as James Rhodes in The Avengers: Age of Ultron. Cheadle himself hinted at it during an interview to talk about his Golden Globe nomination for House of Lies.
Unfortunately USA Today, which got the scoop, doesn’t have the actual quote, but it does say he confirmed that he, “has a part to film in the next Avengers movie,” along with his Miles Davis biopic Kill the Trumpet Player.
So far his character, James Rhodes, has been confined to the Iron Man movies (and was played by Terrence Howard in the first film), so if he is up fro Ultron, this will be the first time he’s joined the expanded universe. He has however previously hinted about having conversations with Joss Whedon about appearing in Age of Ultron. He’s also mentioned that he visited the set of Captain America: The Winter Soldier, but there’s been no word on whether he will be a part of the film at all.
There’s no news either on how he will fit into the Avengers movie, especially considering what Tony Stark did at the end of Iron Man 3.