https://www.polygon.com/2018/7/6/17538458/destiny-2-forsaken-supers-subclass-new-trees-abilities-class

Destiny 2: Forsaken is the star of Game Informer’s August issue, which has finally revealed some of the details surrounding the nine new supers in the upcoming expansion. Each subclass will be getting a new tree in Forsaken to go next to the other two. This new branch will offer a different super ability and some impactful skills.

Each of these new subclass trees will need to be unlocked first — likely through some kind of quest. However, not all of them will be available on day one. In an interview with Game Informer, Forsaken lead Scott Taylor said that it could be one to two weeks between acquisition periods for the new subclass trees.