There is a probability that we might never die. Death is a random event which might split the universe into two possibilities that in one scenario I am dead while in the other I might still be alive. Each possibility is a universe in itself. The hypothesis comes from Quantum Physics which says that for any random event there are infinite paths that the observer might take to reach from point A to point B suggesting there might be a path in which the observer never die in reaching from point A to B.
There is a state of Quantum superposition in which an observer might be alive and dead simultaneously. Believing death to be a radioactive decay of atom and a random event, there is a state of the atom in which it could well be dead and alive at the same time. Thus implying there is a case of Quantum immortality that the Quantum superposition resolves itself into splitting in two dead and alive possibilities of which the alive possibility is the one where the observer is not dead.
The implications of Quantum superposition is that there might be parallel universes in which an observer continues to live and such universes are infinite about a millimetre in difference from the one which we inhabit. Then why don’t we choose the universe with any other possibility regardless of death? Then why don’t we see the other possibility for any random event other than death? Because our consciousness does not branch unless we die or in the other words we continue to live in the same universe. Then we don’t see the immortal people around because our universe triggers death and they choose the one with the life.