Cynthia Kaye McWilliams is one of Hollywood’s most versatile actors. Currently appearing opposite Kevin Hart in “Real Husbands of Hollywood,” which has just returned to screens for a reunion season after a six year hiatus, McWilliams is also the voice of Gamora in Marvel Studios’ animated series “What If…?” and is soon to be seen in Apple original series “The Last Days of Ptolemy Grey” alongside Samuel L. Jackson.

The six-episode drama, based on the novel of the same name by Walter Mosley, sees Jackson play a 91-year-old man almost lost to dementia who has one last chance to regain his memories. In doing so, he has to try to come to terms with his past and also, hopefully, solve his nephew’s mysterious death.

McWilliams, who plays Jackson’s wife, Sensia, in the show, spoke to Variety about working with Jackson, stepping into Zoe Saldana’s shoes and...