They promised us that Captain America: Civil War would change the course of MCU history, and boy were they right. By the end of Cap's third film, the Avengers are divided. The battle over the Sokovia Accords has left the characters wounded, literally and figuratively, with their friendships in tatters.
Beyond that, the accords themselves have set up a situation where Team Cap is forced to go on the run, or stay incarcerated in the Raft. Team Iron Man, for all their victories, are left to lick their wounds, and Black Widow is AWOL. No one gets out of this conflict unscathed, which sets up a really interesting situation for the Avengers in the future.
Team Iron Man: Accord-Approved Avengers
The characters who sided with Tony Stark and signed the Sokovia Accords are now legit Avengers, sanctioned by the UN to act to save others — when the oversight committee deems it necessary, of course.
Yet ironically, after Civil War's end, this is the most fractured team. Three of the characters have left for one reason or another. T'Challa returned to Wakanda (sheltering Bucky Barnes), Natasha went on the run after acting to protect Cap and Bucky, and Spidey swung back to, well, school probably. (And as a minor, Peter wasn't even sanctioned by the accords to act anyway. Tsk tsk, Tony.)
Even the remaining Avengers are out for the count. It's going to take a while for Rhodey to learn to walk using Tony's paraplegic technology, and we don't know if he'll ever be fighting fit again. Vision is wallowing in grief and guilt, according to Paul Bettany, after he caused Rhodey's injury. Tony himself is probably the only Avenger left who might actually leap back into hero work, which is an interesting turn of events, seeing as he was thinking of retiring in Age of Ultron.
(Oh, and as Bruce Banner and Thor didn't sign the accords, they're not sanctioned to act, either. Who even knows what's up with Netflix's The Defenders? They might be outlaws now.)
So Team Iron Man has become basically just Iron Man, and that's if he even wants to be an Avenger any more. It'll be very interesting to find out how this progresses, and whether we've come full circle back to the situation in the first Iron Man film. But it's a fair bet that eventually, Tony will team up with Team Cap again. After all, he can't fight Thanos all by himself. And speaking of the Star-Spangled man:
Team Cap: Secret Avengers?
At the end of Civil War, Steve rescues his teammates from the Raft, leading them off into hiding.
So what's next for Team Cap? Considering Steve's career has mostly consisted of his defying orders and doing whatever the heck he wanted, it's highly likely he'll continue being a superhero, regardless of how legal it is. Sam "I do what he does, just slower" Wilson, will probably follow suit. As for the others, none of them can return home, thanks to the whole fugitive thing (which must be a bummer for family man Clint and trying-to-be-a-responsible-dad Scott).
Wanda doesn't really have a home, so this might seem like a nice change of pace for her. But thanks to the accident that sparked this whole issue, Scarlet Witch is seen as a liability at best and a menace at worst. She might want to lie low for a while. Alternatively, becoming a secret hero might allow her to redeem herself, one heroic act at a time.
It's going to be really interesting to see how this situation progresses, if Cap and his teammates continue to save the day. They'd have to be a lot more covert, operating outside the law and keeping out of reach of the UN authorities. This is actually something we saw play out in the Secret Avengers comics, which were critically acclaimed.
Because the Avengers are divided now, it's possible that the Infinity War films could be a divided story, following up on the situation after Civil War and showing the two Avengers teams working separately. It would make sense for the story to explain how the two teams are brought back together, but before Thanos attacks Earth we could well see Team Iron Man (or maybe just Tony and Vision) sent after Cap's Secret Avengers to bring them in. Ultimately, though, the two teams will no doubt come together again to battle Thanos, albeit a little worse for wear.