The Man from Earth: Holocene

The plot focuses on university professor John Oldman, now calling himself John Young, who is secretly a Cro-Magnon man (or Magdalenian caveman) who has survived for more than 14,000 years. However, despite all those years of immortality, John has found that he has begun to age and he no longer heals as quickly as he used to. Meanwhile, four of his students have begun to suspect the truth about him and contact Art Jenkins, whose career fell apart after publishing a book about John's story.