One of the biggest strengths of Helldivers 2's live-service model has been its Major Order mechanic, whereby every week or so the entire player-base is given one big goal to work towards. These Major Orders have ranged from killing a certain number of enemies within the span of a few days, to liberating entire sectors from Automaton control over the course of a week. It's not the first time widespread challenges have been used in a live-service game to retain a player-base, but it perfectly fits Helldivers 2's overarching galactic war narrative.