Microsoft has announced that Microsoft teams will offer End-to-End Encryption. The initial preview will be limited to 1:1 unscheduled calls, but Microsoft plans to expand this to scheduled calls and online meetings over time.
https://www.techradar.com/uk/news/microsoft-teams-is-finally-getting-end-to-end-encryption-and-bunch-of-other-security-upgrades
https://www.theverge.com/2021/3/2/22308915/microsoft-teams-end-to-end-encryption-support-e2ee