Just like with other games in the series, Call of Duty: Black Ops 4 is full of Easter eggs, most of them references to other games in the franchise.
But since the game doesn't have a campaign mode (the first in the series to do so), some of the Easter eggs can be difficult to spot. It's a given that your main priority in multiplayer and Blackout is to frag your opponents and get the #1 position -- not look for Easter eggs.
From references only available in co-op mode to zombies and battle royale, Black Ops 4 does right by paying homage to some of the best moments in the series. If you like unlocking secret references in Call of Duty games, then follow our guide for the 7 best Easter eggs in Black Ops 4.