Challengers, Luca Guadagnino’s sexy tennis drama, is so focused on the fierce threesome of stars Zendaya, Mike Faist, and Josh O’Connor that once a new character comes into play, it takes a lot to stand out. Thankfully, Darnell Appling, who plays the umpire, hit the serve back hard when he was unexpectedly asked to co-star in the movie alongside his boss, Zendaya (he’s been her longtime assistant). At the Challengers movie premiere in Los Angeles Tuesday night...