I was taking the question meaning
from this point forward.But obviously,several others have died before now.
Ok, we will stop being professor pedantics, lol, and think of possibilities for the future.
Well, thinking about the comics, perhaps one day someone will kill off Robin in a Batman series, I don't think that will happen anytime soon, but decades from now, yeah, I think someone will do that storyline as part of a trilogy.
I don't know why people think they will kill off Superman in the films, well, in the near future anyway. But much like the Robin storyline, they will most likely do the DOS story at some point, but not for at least another decade or two.
The most likely scenario for heroes getting killed off in near future films? Any of the team movies where they have a huge roster to pick from for future films, so x-men, avengers, justice league, etc, is the most obvious answer. They might do the death of Thunderbird in an x-men film, as he was the first of the new x-men to die in the comics.