This request is still on the backlog.
Teams is already threaded! Just make sure to use the “Reply” button instead of the bottom compose bar when responding to someone’s previous post. That will thread the conversation.
Thank you for your feedback. We’re happy to announce this is now available to users who opt into Public Preview.
You can learn more about the Microsoft Teams Public Preview program here: https://aka.ms/TeamsPublicPreview, and Teams administrators can find documentation to manage which users will see the Public Preview option here: https://aka.ms/TeamsPublicPreviewAdmin