https://www.gamespot.com/articles/destiny-2-season-1-ends-soon-weekly-reset-brings-n/1100-6455242/

Next week marks the launch of Destiny 2's first expansion, Curse of Osiris. Coinciding with that, the first "season" of content will come to an end, bringing a refresh to certain aspects of the game. For now, the final weekly reset of Season 1 has taken place, introducing a new (and familiar) Nightfall Strike, Flashpoint, and Eververse lineup.