Microsoft today announced details for the Teams developer platform, also confirming that Microsoft Teams is finally coming to the Store on Windows 10. It's available in preview beginning today, exclusively for devices that are running Windows 10 S / Windows 10 in S mode.
But the Teams app that's coming to the Store is a Progressive Web App, or PWA. Support for PWAs arrived in the Windows 10 April 2018 Update, and they allow for web apps to run like native apps using Service Workers. That means that if you're not on Windows 10 S, you can still test out the new app by simply using Edge on Windows 10 version 1803, because that's essentially what this is.
Microsoft says that the app supports the Narrator screen reader, integrates into the Action Center with notifications, and more.
The current Teams app, which is not in the Store and is not coming, is built on Electron. Getting the app from the Microsoft Store will also allow for the Store to manage updates, so that's one less thing to run in the background.
Microsoft didn't offer a link to the Store listing in its announcement, but if it uses the same listing as it does for Windows 10 Mobile, you'll be able to find Teams here.