Immortality is possible in Diablo 4. You just need the right build and a little ring that might take a while to get, but it's possible, as demonstrated by YouTube user Emilyheartz987.
In one of Emilyheartz987's recent videos, a max-level Butcher spends 20 minutes trying to kill them as they stand there without attacking. Their health bar doesn't budge as one of the hardest bosses in the game tries to cleave them down. Emilyheartz987 is so confident that they casually tweak their skills as the one-sided fight goes on.
