At first, it was teased that the third Captain America film would be Captain America: Serpent Society, but it was then confirmed that the speculation and rumors as of late were correct:
May 6, 2016 will be the date when Captain America and Iron Man square off against each other in a story influenced by one of the biggest events in Marvel history.
For those who are not aware, the Civil War storyline featured Tony Stark as the head of a Superhero Registration Act that Steve Rogers was adamantly against. While the man stuck in the middle was Peter Parker and we can assume Spider-Man will play absolutely no role in this adaptation, nor will this event be inspired by the Stamford incident from the comics as opposed to Avengers: Age of Ultron, we should all definitely keep our eyes peeled for references to the comic book storyline.
Update: It has been announced that Chadwick Boseman will be playing Black Panther AND that he will appear in this movie before having a solo outing!