Teams and Private channels

In Microsoft Teams you can create private channels and you can have up to 30 private channel, private channels are used to have special channel and creates separate site collection to keep the data confidential to specific audience.

There is a limit of 30 private channels in each team.

Incase you delete a private channel till the blog time, it will be counted in the 30 channels you have and till now no way to completely delete it, but you can restore a channel and rename it and clean un needed stuff.