If you have acquired a legal PKG file (for example, via a backup or for a jailbroken console), you can install it using these methods: Call of Duty Black Ops 4 - PS4 Games

Black Ops 4 takes place in a post-apocalyptic world, where a catastrophic event has devastated the globe. Players are thrust into a world of chaos, where they must navigate the ruins of civilization and confront the threats that lurk in the shadows. The game's story is told through a series of intense and cinematic missions, which set the stage for the game's multiplayer mode.