The Shootist (1976)

Afflicted with a terminal illness John Bernard Books, the last of the legendary gunfighters, quietly returns to Carson City for medical attention from his old friend Dr. Hostetler. Aware that his days are numbered, the troubled man seeks solace and peace in a boarding house run by a widow and her son. However, it is not Books' fate to die in peace, as he becomes embroiled in one last valiant battle.