Warning! Mild spoilers for Avengers #46 ahead!
The massive 2012 crossover Avengers vs. X-Men divided fans as much as it did Marvel's heroes, but the publisher seems to be acknowledging that the event ultimately did not have much impact on its universe. While at least Captain America still remembers the battle over the Phoenix Force, it didn't stopped him from later fighting for the cosmic entity and letting its host join the Avengers.
Avengers vs. X-Men begins with Earth's Mightiest Heroes detecting that the Phoenix Force is heading towards Earth. Believing that it is looking to possess Hope Summers — who at the time was considered the mutant messiah — the Avengers are determined to prevent this powerful force of cosmic destruction from arriving and threatening all life on Earth. When Captain America leads a squad of Avengers to the mutant island of Utopia to take Hope into protective custody, mutant leader Cyclops refuses and war breaks out between the two teams. The Phoenix ultimately ends up possessing five X-Men, who reshape the world in their image of perfection. Cyclops turns into the Dark Phoenix and kills Professor Xavier before a united team of X-Men and Avengers finally take him down and rid the world of the Phoenix.
The Phoenix did not stay away forever, and a recent story arc in Avengers saw different heroes compete in a tournament to become its new host. In the end the Phoenix chose Maya Lopez, aka Echo, as its new host. In Avengers #46 by Jason Aaron, Javier Garrón, David Curiel and Cory Petit, Captain America and Black Panther are conducting tests on the new Phoenix as well as the new Starbrand. Cap is concerned about letting the newly powered Echo into the field and says, "Maya, while you've been a valued Avenger before, you now wield a power that I once went to war over, to keep it away from the Earth." Starbrand points out, "Looks like you lost that war." Captain America brushes past this and reiterates that he has reservations about keeping Maya on the team. Black Panther says that they should utilize these two ancient powers, and adds that Steve already let them join his team during the Heroes Reborn event.
The brief exchange highlights the ultimate futility of the whole event. While Cap does admit that he has reservations, his protests don't rise above a fairly polite conversation with Black Panther about why Maya should maybe not be put out into the field. This is a man who believed that the Phoenix was so dangerous that he was willing to risk his life and the lives of all his fellow Avengers in order to stop it from arriving on Earth. If he's willing to take part in a tournament to become its new host, and then later doesn't try to stop Echo from entering Avengers Mountain and possibly join the team, then what was all that fighting about in the first place? If he had taken the same approach in 2012 and calmly expressed his concerns, a lot of chaos and destruction could have been prevented.
At the time of its release Avengers vs. X-Men received mixed reviews. Many believed that the characters were too quick to rush into violence, and that the whole event was really an excuse for a lot of scenes of superheroes punching each other. Few people look back on it as one of their favorite stories. At the end of the day, the crossover did not really matter and everything that happened in it has been reversed. The Avengers and X-Men get along now (for the most part), Cyclops is a hero again, Professor X came back to life and, despite Captain America's reservations, the Phoenix is on her way to becoming a key member of the Avengers.