https://www.gamespot.com/articles/destiny-2-updates-and-live-events-will-be-split-in/1100-6454249/

During its stream at Twitchcon today, Bungie revealed a lot of information about the future of Destiny 2. Players can look forward to frequent updates and new events, which come with new game modes, cosmetics, and gear.

First, Bungie announced that Destiny 2's future updates will be organized into four "seasons" per year. We're in the midst of the first season, which has so far featured Faction Rallies and Iron Banner as its main limited-time events. These seasons will feature different "themes", which will be defined by special cosmetic items. This means that some items will vanish once Season 1 ends, however.