We don’t know exactly how he’ll come back, but rumors indicate that Superman could be wearing a black version of his costume and one can only hope that it will be accompanied by a beard and mullet.
Dead or not, you can’t have a Justice League movie without Superman (Henry Cavill).
Though the character met his untimely death at the hands of Doomsday, Superman is nonetheless returning to the world of the living in Justice League, and Warner Bros. hasn’t been shy about showing off the Man of Steel in promotional images, either.