There is no separate Securlet for Microsoft Teams as of 13 May 2022
Microsoft Teams file upload/download is tracked by Office 365 Securlet as a Sharepoint site.
Content Inspection for MS Teams Chat Messages is on CloudSOC Securlet PM's roadmap.
But can only be developed AFTER Microsoft updates their API to enable such inspection.
Depending upon Microsoft, this is projected to be developed by our Securlet Dev team in latter half of 2022