This is the first time a Bond girl has returned (unless you count Moneypenny or Dench's M) since Sean Connery's Slyvia Trench (Which was mainly intended as a bit of a running joke) who appeared in two films, although there was some discussion of Michelle Yeoh's Wai Lin and Halle Berry's Jinx returning.
I'm guessing this means she'll probably get killed off like Tracy Bond and this will be the catalyst for Bond's mission, as Bond seemed to be about to semi-retire at the end of SPECTRE, and it's been said that this new Bond will wrap up the story that began in ROYALE, although there's been no news of Waltz coming back just yet. (Maybe SPECTRE has a new leader?).
https://www.empireonline.com/movies/...naomie-harris/