This mod let's you toggle the HUD on/off with caps lock. You can also toggle weapon laser beams off with F1 (hotkeys can be changed)
Be aware that this will also toggle the menu, button prompts and certain black screens during cutscenes.
I have only tested this in singleplayer, I don't know if it's bannable in multiplayer but it seems to be fine if you stick to singleplayer.
Update: One user reported it not working with the Battle.net version, so it might only work with the Steam version.
Installation:
1) Download Reshade with full addon support, select DirectX 12 rendering API and click next.
2) When Reshade prompts you to select effects to install click next (and not the skip button) after that you will be prompted to select add-ons to install.
Select ShaderToggler by Otis_Inf and click next.
3) Download the ShaderToggler.ini from the files section of this mod page and drop it in the main folder: Call of Duty Black Ops Cold War
Done.
Changing toggle key:
Open Reshade with the Home key, click the Add-ons tab at the top, click the little arrow next to Shader toggler and click List of Toggle
Groups.
Click the edit button and just change the key shortcut, press OK and then Save all toggle groups.
Controller support:
There's no native controller support, but you can use a program like Controller Companion and make a profile where you bind an Xbox button to caps lock.
(Just make sure Controller Companion is activated ingame by pressing both start and back at the same time)