Reboot your computer in case you have pending installs.
For issues with antivirus software:
If you are running an antivirus software, we recommend adding the entire Call of Duty: Black Ops 4 game folder to your antivirus exception list.
For Comodo users: Select Settings → Advanced Protection → Miscellaneous → Detect Shell Code Injections [Exclusion] and add the entire Call of Duty: Black Ops 4 game folder to the exclusion list.
For BullGuard users: Select Settings → Main and uncheck Self protection.
If issues still persist:
If you are using Razer Synapse, make sure to update to the latest driver.