Call of Duty: Black Ops 4 is the 2018 annual release in the Call of Duty series and is making a drastic change with dropping the campaign mode to add the new Blackout Battle Royale and further focusing on Treyarch's Zombie mode.
Here's a description from the Humble Store:
Call of Duty: Black Ops 4 features gritty, grounded, fluid Multiplayer combat, the biggest Zombies offering ever with three full undead adventures at launch, and Blackout, where the universe of Black Ops comes to life in one massive battle royale experience. Black Ops 4 will be the most robust, refined, and customizable Call of Duty PC shooter experience ever created with uncapped framerate, 4K resolution, HDR, support for ultrawide monitors and additional features built for the PC community.
Multiplayer raises the bar, delivering the most thrilling grounded combat experience yet with a focus on tactical gameplay and player choice.
Call of Duty: Black Ops 4 delivers the biggest Day 1 Zombies offering ever with three full experiences at launch: IX, Voyage of Despair, and Blood of the Dead.
In Blackout, Black Ops comes to life in one massive battle royale experience, combining Black Ops signature combat and the biggest map in Call of Duty history.