Despite the vast differences between the live-action films and television series forming the Marvel Cinematic Universe and the Marvel Comics themselves there still exists and always will be direct comparisons to the source material. Sometimes fans want the adaptations to closely recreate the story beats of certain comic book events, especially when it comes to characters, and other times fans are looking to embrace an original take.
What's for certain is that the reality of different takes across different mediums always results in a little confusion. We saw a bit of this when Marvel unveiled the first full-length teaser trailer for Captain America: Civil War. The film aims to adapt one of the most famous comic book crossover events of all-time, but where Marvel Comics contains decades worth of stories and literally thousands of characters to build off of, the MCU only has a dozen films, each around two hours long. The worlds are very different and therefore the film version of Civil War will be different as well, but similar where it matters most. Much of this centers around the focal point of the Civil War event itself - the Superhero Registration Act.
In the books, Marvel's Civil War was over-the-top and extreme. It focused heavily on the idea of superheroes revealing their secret identities and favored one side over the other, villainizing Tony Stark in a way that didn't make sense. He made a killer cyborg Thor clone who murdered an Avenger. He recruited supervillains, and imprisoned proven superheroes in an inter-dimensional penal colony. It was ridiculous. And much of it was retconned later.
The themes however, were interesting and innovative, exploring the political side of vigilante justice and superheroism. If powered or "gifted" individuals take action on their own and innocent lives are caught in the crossfire, or there's collateral damage, who's responsible? If a super-genius scientist can make weapons of mass destruction or automated killer robots, who regulates this? What gives people with powers the right to fly or teleport across borders without permission? All of these things pose problems, especially when so many gifted individuals aren't necessarily using their abilities for "good."
This is what Civil War did well. In the books, the event began when powered superheroes filming a reality TV show attempted to take down some supervillains - one of whom destroyed a few blocks of a small town, killing hundreds of innocent civilians, including a schoolyard full of kids. That crossed a line the government could not reconcile and so legislation was put in place that required powered individuals to register, reveal their identity, and be trained to use their abilities safely while working for S.H.I.E.L.D..
The sticking point here in the comics is the requirement to reveal identities since this put the families and friends of superheroes at risk to supervillains who don't play by the rules. It essentially created a crippling weakness among all heroes that villains could exploit. Of course, in the movies, this isn't an issue. Secret identities aren't really a thing and there aren't as many heroes. Everyone knows who Captain America and Iron Man are. Pretty much everyone else had their records shared to the world at the end of Captain America: The Winter Soldier when Black Widow leaked it all.
Let's take a look at what Captain America: Civil War's directors have to say about how the MCU will deal with this...