The movie takes place a year after The Last Jedi. The Rise of Skywalker could refer not to the bloodline itself, but rather to a symbolic legacy of the Skywalker name living beyond the family.
The family, as a whole, has an unfathomable impact on the fate of the galaxy. The return of the Emperor implies that this movie will rely heavily on the franchise's long history.
In the film, the vestiges of the resistance face the first order again, while making peace with the past and their turmoil. Meanwhile, the old dispute between the Jedi and the Sith comes to ahead.