Yes, you have access to all of Teams' features and files during a call in addition to other applications on your computer.
When a contact calls you, the Microsoft Teams notification window opens, and you hear the ringing sound.
Click on the Accept with audio icon 
While in the call, you can click back into Teams and open any Team you are a member of and access links and files held within those Teams. You can also open and/or use other applications such as a web browser.
Once you are done with the call, click the Decline call icon 
to end the call and go on with your day.