I should start this post by saying that if, like me, you're included to get very, very upset about the fates of certain Marvel Cinematic Universe characters, you should probably click away. Because we're about to have a heavy conversation about The Snap. Oh yeah.
The Snap, for those of you who don't know, is what Marvel fans call the heart-shattering moment from Avengers: Infinity War when Thanos (that's the big, purple bad guy) finally achieves his goal of obtaining all six infinity stones. Together, the stones give Thanos endless power, which he uses to "restore the balance" of the universe. He simply snaps his fingers, and superheroes start disintegrating left and right. Hence the apt title "The Snap."
In Infinity Wars, fans had to fight tears as they watched Spider-Man, Star-Lord, Bucky Barnes, Nick Fury, and many others turn to dust before their very eyes. However, there are plenty of characters who weren't shown during the snap, and thus Marvel fans were left to assume which secondary characters survived and which ones didn't.
Thankfully, Marvel put them out of their misery. The studio just released a massive series of posters for the film's upcoming sequel, Avenger: Endgame, that has a really, really sad way of separating the living from the dead.