Teams has a new meeting experience. The new experience features include:

• Calls and meetings open in a new window.
• The meeting controls have been relocated to the top of the meeting window. 
• Large Gallery lets you view a grid of 49 participants.
• Together Mode let's you feel like you are in the same shared space.

Enable the new meeting experience

1. Click your profile pic at the top right and select Settings.
   
   
   
   
2. Enable Turn on new meeting experience.
   
   
   
   
3. Quit and relaunch Teams.

More Resources

New Meeting and Calling Experience in Microsoft Teams