The first trailer for Star Wars: The Rise of Skywalker has already led to rampant speculation about how it will wrap up the sequel trilogy’s storyline. Among the many topics under discussion is how the film will continue after the end of The Last Jedi, which left the galaxy in a turbulent state; The Resistance was almost completely crushed, the First Order has undergone a seismic power shift, and Luke became one with the Force. After so much change, some fans have seen the trailer as indication that JJ Abrams is reversing some of the plot elements of The Last Jedi. Even if Abrams hadn’t explicitly stated on several occasions that he has no intention of doing so, a closer look at the previous film shows that The Last Jedi set the stage precisely for the story The Rise of Skywalker’s trailer is telling.
Source: IGN.com Star Wars: Is The Rise of Skywalker Really a Retcon of The Last Jedi?