In Call of Duty Black Ops Cold War the Poison Cabinet Code is 16-75-60.
You can open the poison cabinet in mission Desperature Measures of COD BO Cold War. It’s in the restricted area downstairs, called Kravchenko’s Office in the bottom right corner of the map.
You find out the poison cabinet code by interacting with the computer in the same room and opening the file Nova 6 Entry 2. This reveals the chemical composition of the poison is S-Sulfur, Re-Rhenium, Nd-Neodymium. Now look at the periodic table on the wall of the same room. Each chemical element corresponds to a number of the periodic table. S = 16, Re = 75, ND = 60. That’s the lock combination to the poison locker.
Now input the combination 167560 in the poison locker to open it.
The poison locker combination will always be the same for all players on all playthroughs and isn’t randomized. That’s all there is to figuring out the poison locker key in COD Black Ops Cold War.