Electronic Arts has laid out its plans for Star Wars: Battlefront 2 for the balance of 2018, which will kick off in September with a new Squad system enabling players to spawn on squaddies in the Galactic Assault, Blast, and Strike modes. The 91st Mobile Reconnaissance Corps and 104th Wolfpack Battalion—which is a very Star Wars way of saying "new clone trooper appearances"—will also make their debut.
October will see the release of a new Dark Side hero, General Grievous, followed by Obi-Wan Kenobi for the Light Side in November. November will also see the release of Geonosis, a new Galactic Assault map, the new STAP, BARC speeder, and AT-TE vehicles, and the 212th Attack Battalion clone soldier appearances.
Beyond that, over the less-well-defined "winter," Count Dooku, Anakin Skywalker, the Coruscant Guard and 501st Legion trooper appearances, and a new, non-linear sandbox mode in which two teams battle to bring down capital ships (or keep them from being brought down, I would think) will also be added. The General, the Jedi, the Count, and the Kid will get additional appearances as well.
EA said that the Battlefront 2 development roadmap as it stands is an "advance look into what's coming up," and that more details will be revealed in September.