According to a report by @Vondyispog on X, Black Ops 6 will have crossovers with Halo, Doom, and Gears of War.

After several seconds of combat, we get our first glimpse at a giant mech that the Doom Slayer can use. We also see a dragon across the castle’s arches, incinerating the insides of a giant ...

The Doom Slayer quickly became a feared hero of the ... Players will be able to equip a variety of classic Doom firepower ...