Entertainment Tonight recently unveiled the fruits of their own visit to the set of Avengers: Infinity War in which they interviewed a bunch of the cast members which included the likes of Chris Evans, Scarlett Johansson, Danai Gurira and the king of Wakanda himself, Chadwick Boseman. And in their interview with Evans and Johansson, the question about the whereabouts of Team Cap these past years was brought up, to which Johansson had to say:

When we last saw these characters in Civil War it’s been probably 2 or 3 years that have passed, and our characters have been kind of part of some sort of counter-terrorism unit efforts but we’re flying under the radar, and you know it’s a lot I think when you are on these kinds of missions with no governmental support. You don’t even have the support of just the general public, and you’re sort of running rogue, trying to do what you know is best for the common man but you don’t have someone to guide you or support you.

We first learned about these covert counter-terrorism efforts in the first prelude tie-in comic of Avengers: Infinity War. In it, it was implied that Black Widow did a covert operation in Syria to deal with some alien-weapon smugglers. Beyond that, we don’t really know what Cap and Sam were up to these past 3 years. I’m hoping that we get some hints of it in the film when it comes out.

Source: Comic Book