In August 2022, Microsoft, fairly quietly, announced plans to retire the Linux desktop client for Teams in early December, in Microsoft 365 message center notification MC412007. Previously Microsoft had launched a dedicated Linux desktop client, but it had never reached feature parity with Windows.
Incidentally, Microsoft filtered the message center message to only go to tenants using Linux clients, which makes sense to now overwhelm customers, but I wish there was an option Microsoft partners could tick to get each and every message so they can plan and advise their customers best.
The current Windows/Mac Microsoft Teams desktop app is built with Electron, an open-source platform for building desktop apps. We know that a new Teams desktop app is coming, dropping Electron for Edge Webview2.
Microsoft says that the PWA app will help bridge the gap between Teams on Windows and Linux. The PWA experience is available for both Edge and Chrome browsers running on Linux.
The PWA provides desktop-like app features, such as notifications for chat and channel, a dock icon with respective controls, application auto-start, and easy access to system app permissions.
Microsoft blog: Microsoft Teams progressive web app now available on Linux