If you wish to delete a Vercel Team and effectively cancel your subscription, first ensure all your team's domains have been removed from the team. Once all your team's domains have been deleted, navigate to your Team's dashboard via these steps: Team's Dashboard → General Settings → Delete. If you scroll to the bottom on the General Settings section of your Vercel team settings, you see the second-to-last card labeled Delete Your Team.
Deleting a Vercel team.