In Pokemon GO, new seasons tend to come into rotation every so many months as part of the live-service format in which the game tends to follow. With each new season that occurs, a new seasonal theme is introduced, which man influence the types of wild Pokemon, Egg hatch spawns, Raid bosses and in-game events are available to the player at any given time. Additional in-game celebrations and events may introduce additional Pokemon for a limited time, particularly with the like of certain Raid bosses such as Shadow Raids, 5-Star Raids, and Mega Raids.