Kindly note that delete options are available to Super Admins only, and to process removing a team member from the team or to delete a team, navigate to
Settings → User Management → Teams tab.
How to remove a member from Team
Locate the team from which you'd like to remove user
Click on the "Pencil" button to edit team
Remove member by clicking on the "x" button on the right side of the row user is in
Hit "Save" button to confirm changes
Removing team member will not affect any 
Analytics stats, but only views when Team filter is being used.
How to delete a Team?
Locate the team you'd like to delete
Click on the "Delete" button on the far right of your screen
Pop up window will appear with warning message that action can't be restored
Hit "Yes, I'm sure" button to confirm the delete
Deleting a team will not affect any Analytics stats. Simply, you'll not be able to choose this team as a filter anymore.