Comic writer Mark Millar has had many of his comic book creaton adapted for film, like Kick-Ass, Wanted and the upcoming Kingsman: The Secret Service. The next Captain America film will be based on his ‘Civil War’ comic book storyline. In a recent interview Millar was asked how he felt about Marvel Studios adapting it.
Millar may be a comic book movie consultant for 20th Century Fox, but he didn't let that get in the way of enthusiasm for Marvel Studios. "They’re a money machine, they’re amazing," he gushed. "Whatever they do is gonna be a billion dollar movie and it’ll be great."
The real question is how much of Mark Millar's 'Civil War' storyline will be used in the film. In the seven-issues limited series, Captain America and Iron Man have a conflict over the Superhero Registration Act. Much of that story dealt with mutants, but Fox owns the rights to mutants for their X-Men franchise. Plus, one the main issues is that if a superhero registers he has to reveal their true identity. Marvel films don't really focus at all on secret identities.
I think it safe to assume that Marvel's Captain America 3 will only be loosely based on Millar's comic. I'm sure we'll understand the conflict Captain America (Chris Evans) and Iron Man (Robert Downey Jr.) will have when Avengers: Age Of Ultron comes out. It will plant the seeds.