"Teams" Channel missing
With the latest version of Teams, the "Teams" Channel 
is now combined with your "Chat" Channel 
by default. Click on "Chat" and scroll down in your list to see "Teams" chats below.
To have your "Teams" Channel show separately in the left column again:
- On the top right by your profile picture, click on the 3 dots
- Click on settings,
- Click on chat and channels
- Choose "Separate"
Now you will see them separated again. 