Microsoft Teams - Call Forwarding
Set up call forwarding
To start forwarding your calls, select Settings and more
next to your profile picture at the top of Teams. Then select Settings > Calls 
Under Call handling and forwarding, select the toggle to choose how all call forwarding should be handled, or set up different responses for different scenarios. You can choose to have calls forwarded to voicemail, to a new number or specific contact, a call group, or your delegates.
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Note: Call forwarding is only available in one-on-one calls.