Mank is a personal project for Fincher, as the script was written by his late father Jack, who died in 2003. Considering the personal life of Mankiewicz, though, it could be a lot of fun. According to Welles collaborator John Houseman, "Mank" was "a neurotic drinker and a compulsive gambler, [but] also one of the most intelligent, informed, witty, humane and charming men I have ever known." Welles and Mank famously clashed during the writing of Citizen Kane, but the film won an Oscar -- its only Oscar -- for original screenplay.
Fincher hasn't been sitting around during his feature film hiatus, having produced Netflix's Love, Death, and Robots, an adult-themed animated anthology series. He was set to direct a sequel to World War Z starring Brad Pitt, but the project was shut down over reported budget issues. Oldman, meanwhile, is working non-stop, shooting Steven Soderbergh's The Laundromat for Netflix, along with several other films.