Captain America 3 will officially be called Captain America: Civil War, which means Tony Stark / Iron Man will make an appearance in the film. For those unaware, the Civil War story arc comes straight from the comics, but, chances are, the film won't follow the whole story via the same pattern.
We've long known that there was a possibility Marvel might kick off the Civil War story arc with the third Captain America film in 2016. We've heard rumors of Robert Downey Jr's involvement, though, we do have to wonder if Marvel's hand was forced due to DC's Batman v Superman: Dawn of Justice.
Captain America: Civil War is leading up to a possible battle between Iron Man and Captain America himself, as both do not see eye to eye when it comes down to a new government backed law that is called the "Superhuman Registration Act."
From what we understand, Steve Rogers is in favor of the new law, and he's leading a group of warriors who are also in favor of the law. Tony Stark, on the other hand, is not in favor of it, and obviously there will be others who will take his side on the matter.
What we end up with is two groups of heroes who have a different view on the world and what the government should and should not be doing. It causes a massive battle but mainly between the Captain and Iron Man.
The events in Captain America: Civil War could be the setting point of which all of Marvel's phase 3 movies are based on. It could cause a rift between heroes that might take several movies to fix, and for some, things might never be the same ever again.
For example, we're certain the government is scared of the Hulk and would rather see the creature dead or gone for good. Tony Stark clearly sees Bruce Banner as a threat since he went ahead and created the Hulk Buster secondary armored suit.
In the end, it is possible some might find a way to send the Hulk to another planet because attempting to kill the creature would take too much effort, a move that would more than likely cause the death of many.
We can't wait for 2016 to see what Captain America: Civil War is all about.