In May 2018, Avengers: Infinity War will take the world by storm.
An unprecedented movie even by Marvel studios standards, Infinity War will unite most of the superheroes the Marvel Cinematic Universe has introduced on the silver screen since the first Iron Man film was released in 2008. A decade's worth of characters will come together for a single story, a massive production rumored to be the most expensive movie ever made. But Marvel, knowing the scale and popularity of such an undertaking, wouldn't stop there. The story of this adventure is so monumental, so vast, that two movies would be needed to tell it properly. Avengers 4 is already coming, and it will be with us sooner rather than later, with a release date set only a year away from its predecessor: May 3rd 2019.
Although the movie was first billed as Infinity War Part 2, that particular subtitle has since been dropped and it is now only referred to as Avengers 4. The fact that the official title hasn't been released yet makes us think that the subtitle will be revealing, or at least indicate its comic book inspiration -- which in turn could lead us to guessing approximately where Infinity War will leave things when the credits start to roll.
When it comes to the Avengers movies, Marvel has always been playing things pretty close to the vest -- we don't know much about Infinity War save for which characters are in it, and the vaguely-defined dangers they'll be facing. The threat is so big, so devastating, that the fate of some characters is definitely up in the air. It's an air of mystery that Marvel definitely wants to keep, which is probably why we know even less about Avengers 4.
However, if you look close enough, there are some things you can find out -- like say which characters will appear in the fourth team-up film. There are rumored cast lists circulating on the Internet right now, but they are just that -- rumors. Here, we will split the difference, and list which characters are actually in Avengers 4. So far.