From IGN:
On stage at EA Play today, EA announced that rather than offering a traditional season pass, Star Wars: Battlefront 2 will instead offer multiple themed content “seasons” as free DLC.
Seasons will be free content updates post-launch, and the first will be released in December with content based on The Last Jedi. The set will include Finn and Captain Phasma as heroes, as well as new planet Crait and a space map above the planet D’Qar. Content in future seasons will include additional planets, heroes, vehicles, modes, and weapons.
http://www.ign.com/articles/2017/06/10/e3-2017-star-wars-battlefront-2-has-free-content-instead-of-season-pass