There are SPOILERS for Infinity War below, so read ahead at your own risk. There is a lot going on in Infinity War with all of the characters, so some superheroes didn't get as much screen time as fans of the Marvel Cinematic Universe had hoped. One of those characters was Captain America, aka bearded Steve Rogers, aka Nomad. Cap played a large part in the movie, but he was rarely seen. However, according to screenwriters Stephen McFeely and Christopher Markus, Captain America will have a big part to play in Avengers 4.
In a new interview, Stephen McFeely and Christopher Markus touched on some parts of their story for Infinity War that were not filmed. Originally, the screenwriting duo had intended for scenes showing what "Steve, Natasha, and Falcon - basically the Secret Avengers - have been up to." As it turns out, the crew was out kicking ass and there were scenes of intense action that were never filmed. When asked about Captain America, Stephen McFeely revealed that the character has a "very intense arc" in Avengers 4.
Part of that "very intense arc" may include Captain America wielding Mjolnir after being deemed worthy. The Russo Brothers touched on the subject in an interview from a few years ago and all but confirmed that either Infinity War or Avengers 4 would have that scene. However, nothing has been officially confirmed at this time and if the rumors and leaks are true, we could very well see the death of Captain America on the big screen after getting teased with it in the promotional material for Infinity War.
While specifics about the story for Avengers 4 are being kept under wraps for obvious reasons, there have been some hints about the story from leaked set photos. Time travel is the one that nearly all fans keep going back to because of a scene that looks like a remake of the Battle of New York from the first Avengers movie. There are shots that feature younger versions of the Avengers in their original suits with Ant-Man around. Ant-Man most definitely was not hanging around the MCU when the first Avengers movie came out.
Again, nothing has been confirmed at this time from anybody within the MCU. But, the Russo Brothers and screenwriters Stephen McFeely and Stephen Markus keep promising fans that Avengers 4 will be unlike anything they've ever seen before in the MCU. That's a pretty bold statement, but if they're able to pull off another feat like Infinity War, all bets are off. Until then, we have the releases of Ant-Man 2 and Captain Marvel to look forward to, both movies will have very important roles in setting up the events in Avengers 4, which hits theaters in May of 2019. You can check out the original interview with Stephen McFeely and Christopher Markus talking about Avengers 4 over at The Playlist.