Johnson's Scorpion King was originally a half-scorpion-half-man antagonist in 2001's The Mummy Returns before he became the human hero of his own movie in the 2002 spinoff prequel The Scorpion King. The movie was set in the desert, thousands of years in the past, and followed Johnson's warrior character Mathayus as he and his allies fought to keep the evil Memnon from conquering and killing more people. Memnon attempted to become The Scorpion King, but ultimately Mathayus claimed the title.
We don't know much about the remake's plot at this point, but we do know that it won't be set in the distant past. Instead, it will take place in modern times, like the negatively received 2017 remake of The Mummy starring Tom Cruise. However, in The Mummy Returns, The Scorpion King was killed, so it's possible this reboot won't take place in that timeline. In the original films, it was never explained how Johnson's character went from hero to villain, so perhaps the remake will delve into that story. Alternatively, we could see an altogether new character take on the Scorpion King title.
It remains to be seen if The Scorpion King will turn out successful, like Jumanji: Welcome to the Jungle's addition to the Jumanji story, or go the way of the box office flop The Mummy reboot. We'll keep you updated on the progress as soon as more information becomes available.