Microsoft Whiteboard App is in preview. Rollout to public users will be coming soon. You can find more details here:
The feature team is still reviewing, there is lots of discussion about this item and I hope to have a decision soon.
-WarrenDavid Rodriguez commented
I hope interest has not declined. This would be an invaluable addition to this wonderful tool. Like many people have already stated, this option would truly make Teams a one stop shop. Our brokers are not interested in dealing with so many different services. The ability to have them live in one place would be a dream come true.