There is nothing in the Quran or Sunnah to indicate that there were any people living on Earth before prophet Adam. Rather the reports that speak of this are the opinions of Quran commentators among the companions and successors. With regard to what some commentators and historians say about a race called Hinn inhabiting the earth, and that the jinn came and killed them and took their place, it seems that this is a story that cannot be attributed to any sound chain of narrators.