Last year, actor Andy Serkis, who played Supreme Leader Snoke in Star Wars: The Force Awakens and Star Wars: The Last Jedi, had to pull out of a scheduled appearance at Keystone Comic-Con in Pennsylvania. This led to the speculation that, like Billy Dee Williams before him, Andy Serkis cancelled his convention appearance at the last minute because of production requirements, specifically that he needed to be on set for Star Wars: Episode IX.
Article source: https://www.cinemablend.com/news/2465288/star-wars-episode-9-rumors---will-we-see-snoke-again