You may need to remove a team that you no longer use or that you don't want anymore.
If you want to delete a team (and you’re the team owner), go to the team name and click More options > Delete the team. Your team will be permanently removed.
Deleting a team removes the team mailbox and calendar from Exchange.
The corresponding SharePoint site and all its files will also be deleted.
And any OneNote notebook, Planner plan, PowerBI workspace, or Stream group affiliated with the team will also be deleted.
Team owners and IT admins can recover deleted teams for up to 30 days.