Marvel always does reshoots on its movies (additional photography is what we like to call this stuff!) and Captain America: Civil War is no exception. The cast and crew are back on set right now, picking up stuff for the upcoming Phase Three opener.
We don't know what they're shooting, but I can tell you this: they're probably not changing too much, because the film has been testing exceptionally well. I have talked to a whole bunch of sources - about five at this point - and they all agree that test audiences have loved the movie. In fact, the only thing they disagree on is whether the movie tested as well as or better than Captain America: The Winter Soldier, which had previously been the best-testing Marvel movie. Further, my sources tell me that the movie doesn't pull any punches in the third act, and that if Marvel execs had been concerned about the film going dark places, these stellar test screenings have alleviated all those fears. So if the test screening audiences are right we're looking at a movie at least as good as Winter Soldier, which could be argued as the best Marvel movie yet.
I imagine we're going to see Civil War marketing ramp up in the next few weeks, possibly starting with the Super Bowl. The first trailer was a huge hit - I'm curious to see what angle Marvel takes with the second, and if we're ever going to get a look at Baron Zemo at all.