Although this is slated basically as 'Captain America 3', one could totally see this as 'The Avengers 3' in that basically, everyone makes an appearance, save Hulk and Thor, and it does have quite a balance going on between Cap and Stark. In fact, it even got to the point where before this was released, the internet blew up with the whole "Team Cap or Team Stark?" question. Of course, most of us went with "Team Stark" for the sole reason that the one and only Spider-Man was actually making an appearance this time around, and he was on that side of things.
'Civil War' starts out with Stark being confronted by a woman who tells him that because of the Avengers, her son is now dead. This is something a lot of action hero films don't address incredibly well - the destruction they leave behind. And yes, before the DC fans jump down my throat, 'Batman v Superman' did it pretty well too. Anyway, Stark brings in Thadeus "Thunderbolt" Ross, now U.S. Secretary of State to discuss the "Sokovia Accords", which is essentially meant to keep our heroes in-check by the U.N., only bringing them in if absolutely necessary. And this is where it gets rather interesting.
While Stark feels a tremendous guilt about what has happened, and more than willing to sign the Accords, Cap sees it as disruptive to their right to choose. For example, what if something bad is going down but it's not "important enough" for the Avengers to help. Cap's biggest personality trait IS that he wants to do what's right, no matter the cost. It gets to be this whole moral compass thing.
On top of all of it, Bucky returns and is blamed for an attack in Vienna where the Accords are to be ratified. The attack kills King T'Chaka of Wakanda, and ends up bringing in T'Challa, his son, as the Black Panther, seeking revenge for his father's murder. With seemingly everyone after Bucky, Cap's old friend, he finds the need to protect him, knowing that whatever he's done in the past had everything to do with being brainwashed.
Of course, this all leads up to one hell of an Avengers vs Avengers fight scene that features everyone who has been introduced so far. The idea behind the fight being "Team Stark" trying to bring "Team Cap" in safely and securely for going against the Accords, while "Team Cap" stands against it all, putting more trust in themselves than a government with a possible agenda.
The Russo Brothers do a fantastic job here, not only in the sense of giving the audience what they wanna see, but working with such a large cast. It's sincerely no wonder why they were chosen to direct 'Infinity War', as they kinda managed to bump Joss Whedon off as THE ensemble cast directors.
On top of everything, it's interesting to see a film in which you can see the positives and negatives regarding each side. As a superhero, would you trust your government to do the right thing at the right time? Could you just sit there and let others take care of something you could take care of much faster? or on the flip side, could you live with the guilt of knowing that in order to save a majority, some casualties may need to occur? It's the first time an MCU movie has come along with that sort of deep thinking attached to it, where one CAN see both sides of the argument quite clearly. This one is a personal favorite of the MCU for me because it triggers that kind of thinking.
MID-CREDIT SCENE: In the aftermath of these events, Bucky chooses to freeze himself again until a cure for his brainwashing - which caused most of the trouble in this, is found. This loosely teases to 'Black Panther'.
POST-CREDIT SCENE: Peter Parker, licking his wounds after the big fight, tests out a spider signal in his room, compliments of Tony Stark, loosely teasing 'Spider-Man: Homecoming'.