Due to recent software upgrades by Microsoft, Microsoft Teams will undergo some interface changes as part of their rollout of the Microsoft Teams Streamline experience.  If you'd like to review these changes further, please use this link to read Microsoft's article on those changes here: Microsoft Teams Streamline Experience Blog.

In order to enable the Teams' Teams and Channels, please go to the 3 dots '...' to the right of the bolded Chat in the Chat section of the Teams application.  Please click these 3 dots, select "Your Teams and Channels".  These channels should now be available below the chat area in one combined interface.  Please reference this image:

You will no longer have the Teams section on the left-hand side.  At the top of the chat section, you will find three bubbled options, "Unread", "Chats", and "Channels".  If you select Channels, this will provide you with an isolated view of just your Teams and Channels.