http://411mania.com/movies/robert-downey-jr-to-join-captain-america-3-for-civil-war-storyline/
Hold onto your hats folks, because this is a big one. Variety reports that Robert Downey Jr. is in talks to play Tony Stark in Captain America 3, which would utilize the famous (or infamous, depending on your viewpoint) Civil War storyline arc. The site notes that the film is set to begin production this spring for its May 6th, 2016 release date. This will be a new film on Downey’s contract with Marvel, as he is already slated for The Avengers: Age of Ultron and The Avengers 3.
The Civil War storyline ran during 2006 and 2007 and was a major moment in modern Marvel history. Following a catastrophic superhero-triggered event in Stamford, Connecticut that leaves 600 people dead–including sixty children at a school that the incident took place nearby–Congress passes the Superhero Registration Act which requires anyone with superhuman abilities to reveal their identities to the government and serve as a peacekeeping force. Tony, who can see where things are going, supports the act as the lesser of two evils (the other being superheroes branded as criminals). Captain America, on the other hand, opposes the act and they end up causing a major split in the superhero community. Cap and others go underground to avoid arrest and many major events happen during the fight, which culminated in Cap’s death.
This would obviously make Stark a villain in Cap 3 and lead to more work for Downey as Stark down the line. Marvel also announced plans today to revisit the Civil War storyline in 2015 as a new Marvel event. What this means for other Marvel Cinematic Universe properties–including Agents of SHIELD, as SHIELD has a heavy role in the Civil War arc–isn’t yet known.