Once Destiny 2: Forsaken launches, Bungie has big plans for "beyond day 1". Players can expect to find information about yesterday's launch of the 2.0 update, as well as brief information about the road ahead through seasons and the annual pass.
Forsaken's launch begins the Season of the Outlaw that provides new "activities and rewards" once the main campaign has been completed. In addition, the blog says, "We've also hidden away many surprises for you to discover. Each subsequent 3-month Season will usher in a month-over-month roll out of new experiences, events, rewards and activities, most of which will be available for free to every Destiny 2 player."
Annual Pass holders will also gain access to a trio of "new experiences" for endgame players with new "activities and modes, discovery, and challenges that escalate, ebb and flow over time, with each offering prestigious rewards". These three Annual Pass "chapters" are called Black Armory, Joker's Wild and Penumbra.
The Bungie / Destiny 2 site has an overview of the content that will be coming in Fall 2018, December 2018, Spring 2019 and Summer 2019. Look for Season of the Outlaw, Season of the Forge, Season of the Drifter and one as-yet unnamed Season. These will run alongside the Annual Pass content in the same time periods.