Sisyphus was indeed punished for his attempts to cheat deat…

Sisyphus was indeed punished for his attempts to cheat death (binding Thanatos, tricking Persephone into letting him return from the underworld), and his punishment - endless, repetitive labor - grants him exactly what he sought: **immortality**. He will never die, never rest, never cease to exist. But this immortality comes stripped of all meaning, joy, or progress.