It'd be Lebron winning regular season MVP and finals MVP in the same season for two straight years, something no one other than MJ has ever done.
Winning MVP and finals MVP in the same year is what separates the all time greats from everyone else. Jordan did it, KAJ did it, Bird did it, Magic did it, Duncan did it, Shaq did it, Olajuwon did it, Chamberlain and Russell did it except finals MVP wasn't around for most of their careers. For whatever reason Kobe gets a pass as the only "All time great" who's never won MVP and finals MVP in the same year.