There's 3 possible meanings:
* the last of the men who walked on the Moon has died
* the last man who stepped onto the Moon for the first time, died
* the last man who ever stood on the Moon before stepping off, died
Perhaps those last 2 refer to the same person, perhaps not.
> Eugene Cernan, the last man to walk on the moon, died Monday, Jan. 16, surrounded by his family.