A few days ago I saw a TV news segment about a couple who adopted a Marine dog with PTSD. They did this to honor their son, the first Marine to receive the Congressional Medal of Honor since Vietnam. He died when he dove on a live grenade to save the other Marines in his squad.
While this was an extreme example of heroism, such self-sacrificing behavior is common enough in our species to raise a challenge to the TOE. Kin selection doesn't explain such behavior, because non-kin are often the beneficiaries. Reciprocal altruism might explain it, but that seems to be a stretch when a young man who has not had an opportunity to reproduce sacrifices his life for others. Perhaps this behavior is evidence for group selection, but most evolutionary biologists seem to believe that group selection plays little, if any role, in evolution.