Call of Duty: Black Ops 3 Cheats - PlayStation 4

Hidden Menu in Datavault
Go to the Datavault in the Safehouse in the Single Player Campaign. In the screen where you unlock Dead Ops 2 (Top left corner in the menu) press Left Trigger, Right Trigger, X and Y to unlock a hidden Menu where you can enter Codes.

Manifest - Get 60-100 Fabrication Kits (does NOT affect the achievement, save to use).
Dreamland - Unlocks Nightmare Mode straight away.

Dead Ops Arcade 2
To access Dead Ops 2, go to the campaign screen and access your safe house. When in your safe house, go to your Data Vault. Move you selection to the top left corner, next to where it says "Data Vault" to what is a small icon. Select this icon, and you are taken to Dead Ops Arcade 2.

Secret Keypad and 80 Fabrcation Kits
Go to your Safehouse,then go to your Data Vault, then go down. You won't see your cursor, much like the Dead Ops Arcade 2 easter egg. Then open it, and and you will see a secret keypad. Then enter the word 'MANIFEST'. You will get no saying if you got it right, but go to your Control Core, then it will be there.

Zombie Mode +5 rounds
At the start of the first round in Zombies, the Shadowman appears on the staircase directly ahead and above. Every headshot gives you +1,500 points and sends you ahead 5 rounds.