Friends Not Showing – Issue Fix
The most typical cause for friends not appearing in your game’s friend list is that they are online in another region. You might not be able to see each other if you’re logged in Europe and your buddies are using Blizzard in North America.
The solution is to re-add them as friends. If you ever move your region again, you may have to repeat the process.
Restarting the game or resetting the crossplay capability in Call of Duty Warzone is another known remedy. Hopefully, the following recommendations may assist you in resolving the issue.