Unfortunately, Microsoft has blocked the ability to use virtual cameras in recent Teams macOS app builds, but you can still use it via web version of teams.

There are some hacks to use it with the app version anyway and more details on the issue below. Feel free to try, but all bets are off and we can't really support you if anything breaks when you do:

https://answers.microsoft.com/en-us/msteams/forum/all/microsoft-teams-mac-os-client-is-not-recognizing/d9e863be-d9a4-4d03-a4b8-1b5c7df58828?auth=1