Microsoft Teams users can now chat with any Teams user outside their organization - Microsoft Community Hub

https://techcommunity.microsoft.com/t5/microsoft-teams-blog/microsoft-teams-users-can-now-chat-with-any-teams-user-outside/ba-p/3070832

https://twitter.com/home/status/1671900694251466754

https://twitter.com/home/status/1671903749567021060

https://twitter.com/home/status/1671934485061943325