When you make a Live presentation, you will soon be able to add a video feed to the presentation. This feature is available using the Microsoft Teams desktop app for both Windows and Mac.
When using the Teams Desktop app, you will now have a new option, Standout mode. When a presenter selects Standout mode all the participants will see the presenters video feed superimposed onto the foreground of the content being shared.
This appears to meeting participants who are using the Teams desktop or mobile app as well as Teams on the web.

Image is not our own. Image courtesy of Microsoft, taken from Message Center email: (Updated) New PowerPoint Live Presentation option with desktop and window sharing
Meeting presenters can customise the participant view before starting

Image is not our own. Image courtesy of Microsoft, taken from Message Center email: (Updated) New PowerPoint Live Presentation option with desktop and window sharing
You can easily enable or disable the video feed during the Live Presentation

Image is not our own. Image courtesy of Microsoft, taken from Message Center email: (Updated) New PowerPoint Live Presentation option with desktop and window sharing
When will this happen?
Roll out is mid May and is set to be complete mid June.