Microsoft, Sony, and Steam accounts can be linked or unlinked by visiting the profile section of the Call of Duty
Please note that unlinking and relinking accounts can cause corruption with Season Pass, DLC, and Micro DLC items applied to your accounts. Please avoid any unnecessary unlinking and relinking of accounts.
Click the gear icon and select Profile.
Scroll down to the Consoles section to link or unlink a console. To link, select a console you wish to link. To unlink, select a linked console.
When linking an account, you will be temporarily taken to the console manufacturer's website to confirm your credentials. Once confirmed, your console will be linked to your Call of Duty account.