Superman, he probably is one of the most powerful superhero ever. So can Superman ever die?
No one knows a clear answer to that but as we know that whatever comes to existence must end, probably may that be Superman too.
There are two possibility for the death of any superhero, it can either be his arch nemesis killing him or his aging. In case of Superman aging is super slow so it would take like a hundreds of century for him to die naturally but if someone like Darkseid takes him down I won’t be surprised.
It’s even totally up to the writer, like in DC One Million in 853rd century, original Superman is still alive but in the future setting of The Legion of Superheroes Superman is not alive. As you can see both are different arcs by different writers. So theoretically in the comic-verse anything is possible.
It is also known to us that Superman gets more powerful as he gets older, as he learns new abilities and skills over time. We also know that Superman’s main source of energy is the yellow sun. The more yellow sun rays Superman absorbs the stronger he gets, basically every type of star can fuel Superman except Red Stars.
On Krypton, aging was a normal process as that planetary system was powered by a Red Sun. Red star made them like a normal human. So if ever Superman thinks of dying he should probably go in a planetary system which is powered by a Red Sun as there he would probably be like a normal human.
Long story short, Superman can die but if he keeps himself fueled he might just last long enough to be called something close to being immortal.