Kylo, who is Ben Solo, the son of Han Solo, dies redeeming himself, but through Rey, he will continue to live. Han Solo appears in the unconscious Ben and helps him to see that his purpose is to save Rey.
The last scene is Rey looking at her reflection, and she sees Ben staring back at her. He will inevitably fall to his untimely death in the film, and the massive battle at the end of the film foreshadows that death is on the horizon.
The conclusion of the movie will leave a door open for more sequels starring Rey, who's now a fully trained powerful Jedi.