With the next two Avengers movies being advertised as the end-all culmination of over 10 years of Marvel movies, you can expect some of the original characters to be killed off by the time the credits roll. As it turns out, the directors the Russo Brothers knew which characters were at the end of their line, and would not be surviving by the end of the films.
Talking to Vanity Fair, the Russo Brothers have confirmed that they have no say in what happens to the MCU after Avengers 4. They've also confirmed some big character deaths will take place in the next two films:
"So we know who we're allowed to kill, and that's about it. I don't even think Marvel had any ideas about where they would go after [3 and 4]. It's not an end for all of these characters; it's an end for some of these characters. So some of these characters will go on. So it's more complicated, that's why it's not a clean ending."
With a the MCU giving us a lot of fake-out deaths (Nick Fury, Loki, Phil Coulson, Daredevil), it would actually be a relief to have some important characters stay dead for once. A lot of people are wanting to see some consequences in the MCU for once. I honestly thought they were going to kill off Captain America in Civil War—like in the comics.
With this news in mind, people are probably going crazy speculating who dies in the film. One popular theory is Vision, what with the Mind Stone being an integral part of the Infinity Gauntlet; Thanos will probably rip it out of his head, killing him. Another is for Captain America, who probably wants to be reunited with Peggy Carter in the after-life anyway.
Avengers: Infinity War is set for a release on May 4, 2018.