Allow Guests to Share Screen
While guests can now join a Team meeting, there is no "promote to presenter" option to allow them to share their screen. Without this, I'm forced to fall back to Hangouts or Zoom.
Daniel B commented
Microsoft is working on this one. Better to track/vote on this one: https://microsoftteams.uservoice.com/forums/555103-public/suggestions/36131932-allow-anybody-to-share-their-screen