The Russo bro's speaking about Cap 3, along with the process of working with Marvel. Marvel has certain things that they want to touch upon in a film, but it's up to the writers on how they go about it. This kinda explains all the clashes we hear between directors and Marvel.
"If you’ve been talking to Kevin [Feige, President of Marvel Studios] the title has been in place probably for ten years in his brain," said Joe Russo. "It’s all part of the road map that he’s laid out, and it’s all part of the bigger plan." Asked if they were building towards Captain America 3
in The Winter Soldier
, Joe explained, "Yeah, I think the way Kevin does it is there are big pieces that he knows he wants to build towards, but the way that you get there is open to interpretation and improv a little bit." He continued, "That’s defined by who gets involved with the project, the writers and directors involved in the project. The big thing we knew we had to deal with in Captain America 2
was the fall of Hydra. Similarly there is a very, very big idea at the center of Captain America 3
. But how we get there is all up to us. And I think why Marvel has been so successful is because it’s been such a clear plan, that everything is interconnected and they’re building emotional capital with each movie that you can then trade off of in the next film."