The show is about a wheelchair-bound police detective, Robert T. Ironside, played by Blair Underwood. Trivia side note: hardcore fans know that Bruce Lee guest starred on an episode of the original Ironside, "Tagged For Murder," in 1967. Here's a cool vintage video clip of Bruce in action.
Choi is perhaps best known as Jim Morita, one of the Howling Commandos in 2011's Captain America: The First Avenger (or maybe you remember him for his awesome William Shatner impression in that one Priceline commercial). In Ironside, he will play Captain Ed Rollins, Ironside's supervisor: