Effective August 1, 2020, Microsoft Advanced Communications for Microsoft Teams is available. This add-on to any paid Microsoft 365 or Office 365 subscription provides a new set of capabilities for large meetings up to 20,000 participants, communication policies, and integrations, in addition to advanced tools for IT management. Microsoft Advanced Communications is only available through the Enterprise Agreement (EA), Enterprise Subscription Agreement (EAS), Enrollment for Education Solutions (EES) and Microsoft Products and Services Agreement (MPSA).
For further information on Microsoft Advanced Communications, please visit: https://www.microsoft.com/en-us/microsoft-365/blog/2020/08/03/take-communnext-level-microsoft-teams/ and you may also check out: https://docs.microsoft.com/en-us/microsoftteams/teams-add-on-licensing/advanced-communications.