This feature request is still being worked upon.
I am still trying to get details on what we could expect for Cortana in Teams and will share examples once something is available.
Step 1: Show cool off AI at Ignite conference
Step 2: Release new productivity and collaboration product that mimics slack in a lot of ways
Step 3: Sideline cool AI that could separate Teams from Slack and Discord
Step 4: Have users' first interaction with new latest product be with T-Bot, the window-licker of AI
We acknowledge the customer demand for Private Channels and have been hard at work on it. Private Channels is currently in preview with a select group of customers. We expect to release the feature to the public later this Fall, and will update here when we are starting to roll out to all customers. We appreciate all the feedback you have provided to us on this forum and thank you for your patience.
This feature item is still in the works. We will keep you posted as we have new info from the feature team.