Treyarch and Activision may have dropped single player campaign from Call of Duty: Black Ops 4 but that didn't reduce the file size for the game. According to a back cover on PlayStation 4 cases, the game will require over 100 GB disk size.
Call of Duty: Black Ops 4 will apparently not lack content as over 100 GB required disk space is not a joke. Then again, it could be required for future assets that will inevitably get added to the game as Blackout mode pretty much spells out "live service".
Fortnite is making a killing with all the skins the game sells, so it's only a matter of time when cosmetics will be up for purchase in Call of Duty: Black Ops 4. Sure, other games feature sold cosmetics as well and don't require as much space but keep in mind that Call of Duty: Black Ops 4 is a newer game, with rather fancy graphics and will possibly live to see the next generation of consoles.
Xbox One store states that the required disk space is only 42 GB which further compounds the theory that the 100 GB mark is reserved for post launch content. While the box cover for PlayStation lists the high 100 GB requirement, there is no indication of what the size might be on the back of Xbox covers.
Considering that the hypothetical additional size includes over 58 GB, it's possible that there are more maps on the way for all modes, including Zombies and Blackout, that we were not introduced to previously. If all the space does turn out to be reserved for cosmetics that will be sold, let's hope it's good enough to justify the size.
Call of Duty: Black Ops 4's release date is just over a week away from release, on 12 October 2018 and not all news is good for the game. For example, the game will not have uncapped frame rate option on PC, which could potentially ruffle some master race feathers.