They're very handy if you want to reach Prestige Master.
Here’s how to use XP Tokens in Black Ops Cold War.
How To Use XP Tokens On Black Ops Cold War
To use XP tokens in Black Ops Cold War, you'll have to earnt them!
XP Tokens are earned through the Cold War Battle Pass system.
These range from 15-60 minute tokens, granting double XP, for general XP and weapons respectively.
To activate them, you'll see a prompt on the main multiplayer menu - which is usually L3 (clicking the left thumbstick in).
Select whichever token you wish and it will be active!
Beware, these run based on time past since activating them, not in-game; so be ready to rock and roll!