Teams add-in for Outlook

By default, meeting requests from one person to another in a Team are appearing in Teams in the Activity area. If you want to stop this, it's a Com add-in to Outlook:

In Outlook, go to File/Options/Add-ins/Next to Manage: Com add-ins at the bottom, click Go...

And uncheck the add-in for Teams Meeting Add-in for Microsoft Office, and click OK: