Even with the heavyweight championship at stake, most of the hype as well as interest in UFC 203, came from the unique story of former pro wrestling superstar C.M. Punk making his UFC debut.
The story told is that this was a major star making millions who left his former business because he wanted to try MMA. Unlike pro wrestlers who went into MMA with major fanfare like Brock Lesnar and Bobby Lashley, Punk had no pedigree as an amateur wrestling champion, or any athletic credentials to speak of. He never played sports in high school. He had taken a few martial arts classes as a kid an trained at times with Rener Gracie in Jiu Jitsu.