[Tom4784]

One of the main theories is that (potential massive spoilers since it's pretty likely)

Spoiler:

Cap will die but the film will end on a cliffhanger as it's revealed that he is a Skrull and that we never actually met the original cap as the Skrulls have had him since he went into the ice.

That'll lead into Captain Marvel and a secret invasion plotline for Avengers 4.

Hawkeye's definitely dead though, I think. I think a lot of other exits will just be characters moving on.