While it is the fourth production season, Fox broadcast these episodes across its fourth and fifth seasons.
Season 4 was initially intended to be the series finale following Fox's decision to cancel the show due to low confidence and erratic scheduling. Consequently, the season contains several "landmark" episodes that resolve long-standing mysteries, such as Leela’s true origin and Fry's destiny as "the chosen one". Futurama - Season 4
Season 4 features some of the highest-rated and most influential episodes in the entire series. Futurama Season 4 Ratings - IMDb While it is the fourth production season, Fox