This offer is available on PC (through Origin), PS4, and Xbox One. However, if you're on the latter platform, it seems like you'll need an Xbox Live Gold membership to grab the season pass; PlayStation Plus doesn't appear to be required for the PS4 version. You can claim the season pass through the links below
Whichever platform you grab it on, the season pass will entitle you to all of the DLC expansions released for Battlefront. That includes some solid ones, such as the excellent Death Star-themed DLC. These consist of new maps, modes, and Hero units, among other things.
Star Wars Battlefront II is slated for release on November 17. Unlike its predecessor, it will not have a season pass--all of Battlefront II's maps, modes, and characters will be free. However, a microtransaction system will be present.
Source: GameSpot