https://docs.microsoft.com/en-us/microsoftteams/quick-start-meetings-live-events
Meetings in Teams include audio, video, and screen sharing for up to 300 people. They're one of the key ways to collaborate in Teams. And you don't need to be a member of an organization (or even have a Teams account!) to join a Teams meeting—just look in the invitation for instructions about calling in.
Live events are an extension of Teams meetings that enable you to schedule and produce events that stream to large online audiences - up to 10,000 people. If you need a meeting for more than 300 people, use a live event.
Webinar Zoom Microsoft Teams Live Events