Limit Access to Specific File Folders
Why can't I limit user access to specific folders in Teams?
@Traci - I would have to disagree with the below comment.
You can change permission settings of folders using Sharepoint. By providing access to certain people in your team it meant only they will see the folder in Teams. Other people in your team who you have NOT given access cannot see this folder. Explanation:
Unless by "folder" you mean channels - then please ignore the above!
Private channels is the feature that will handle this for you. You can track this at: https://microsoftteams.uservoice.com/forums/555103-public/suggestions/16911079-support-for-private-channels