At the end of Captain America: Civil War, we saw Chris Evans' Steve Rogers leaving his shield and suit behind following his violent confrontation with Robert Downey, Jr.'s Iron Man. Many speculated that it was the end of Steve as Cap in the Marvel Cinematic Universe.
And now, the Russo Brothers confirm that Evans' character no longer wears the mantle of Captain America in the MCU. In a recent interview with The Huffington Post, Joe Russo says:
I think him dropping that shield is him letting go of that identity. (It's) him admitting that certainly the identity of Captain America was in conflict with the very personal choice that he was making.
Of course, that doesn't mean that we won't see Steve Rogers again. He will obviously return for Avengers: Infinity War, and he may even take back his Captain America mantle at some point in the movie.
In the comics, however, there was a time when the character gave up his shield, suit, and title, and took up the identity of Nomad. That happened way back in 1974, in the issue Captain America #180 by Steve Englehart and Sal Buscema.
More recently in the comics, Steve handed over the Captain America mantle to Sam Wilson and committed himself to serving as a mission coordinator for SHIELD. So, there are certain alternative courses that Marvel Studios may take regarding Steve Rogers' fate in the MCU.
In another recent interview with Entertainment Weekly, the Russo Brothers reveal what their fail safe plan was at the initial stage of the third Captain America movie. Had they failed to sign Robert Downey, Jr., they would have turned it into a zombie movie! Anthony Russo says:
There was a period where we did discuss a third act that revolved around the Madbomb from Cap mythology…The charm of the Madbomb is that you turn hordes of people into berserkers. That was the physical challenge that Cap and company would have had to face.
Joe explains that the notion of the Madbomb would have meant that Evans' character would have to fight civilians and they would have to decide how he would manage to do that. They always try to put Captain America into such "interesting moral conundrums" due to his nature. He adds:
That would have made a compelling third act, because if civilians are the antagonists, how could he stop them without killing them?
That would have been a very different third installment in the Captain America film series, that's for sure!