Blade runner - I think that is one of the best sci-fi movies. There was a question - what is life and who is human.
Rick Deckard (Harrison Ford) is ex-cop, rehired to find and destroy bio robots, made from human genetic material. He is mostly a watcher, who makes a dirty job. He looks on the reality as a passenger in the train. Replicants are really alive, but theirs days are ending. They are full of life but their lifetime is short, they have die. Realizing that they decide to penetrate to the Earth and find key people who developed their lives. But there is no answer for infinite life, all scientists and engineers were responsible separated parts of their bodies and nobody can help them with one answer - how to not die.
In the final scene Roy Batty (Rutger Hauer) almost killed Rick, but realizing that he is going to end his life soon, decided to save the Deckard's life, and Rick understood, how much replicants love the life.
