What happens to Tom Vincent at the end of " To Build a Fire"?
If you are referring to the main character in this story, he is known as the man. At the end of the story, he freezes to death.
Check the E-notes link on the characters in the story for clarification.
"Then the man drowsed off into what seemed to him the most comfortable and satisfying sleep he had ever known. Later, the dog whined loudly. And still later it crept close to the man and caught the scent of death. This made the animal bristle and back away." (London)