Immortality is a big genetic disadvantage when you want the species to be able to evolve and adapt to its environment. This might have something to do with why

Immortality is a big genetic disadvantage when you want the species to be able to evolve and adapt to its environment. This might have something to do with why most species have limited lifespans. Humans aren't bound by their environment any more though: they can actively control and change their environment, and their own biology. Humans stopped evolving by natural selection ages ago, so there's no good genetic reason to not explore technological means of extending lifespans.