John Cena Backs Out of Crown Jewel to Benefit his Hollywood Status
According to The Wrestling Observer Newsletter, the belief is that John Cena was advised that working WWE Crown Jewel would be looked at negatively in Hollywood when it comes time for him to transition to movies full time.
The original idea for the World Cup was to mix up the brands with Raw vs. SmackDown matches. There was reportedly a plan to do a John Cena vs. Rey Mysterio match with Mysterio likely going over. WWE changed plans when Cena backed out and they went with the brand-specific opening rounds.