Daily goals the game gives you to achieve for extra XP. Usually something like win 3 online matches, heal 10 teammates, or capture 2 flags. Basic skinner box methods to get the player on the game every day.

Daily quests. Missions that you can repeat every day for some recompense. Maybe they are always the same, maybe you get a different selection from the pool each day.

It’s MMO/Phone Game design that has bleed into every other games as a service to ensure engagement.