No one’s ever really gone. Luke Skywalker says it himself in the first teaser for Star Wars: The Rise of Skywalker. Or at least his voice says it. We don’t see Mark Hamill in the trailer, but we know he’ll be in Episode IX, the final film in the Skywalker Saga. That was already revealed, but it wasn’t clear how he would be shown in the final movie, since Luke died in Star Wars: The Last Jedi.
Article source: https://www.cinemablend.com/news/2475441/mark-hamill-confirms-the-peculiar-way-luke-returns-for-star-wars-the-rise-of-skywalker