Today, Microsoft announced the Office app for Windows 10, which is the successor to My Office. In fact, with the launch of Windows 10 over three years ago, the app was originally called Get Office, and it's evolved over time.
The feature-set of the app hasn't changed that much, although it's now a PWA that should be more similar to Office.com. You'll find all of the Office apps in one place, and it's meant to allow you to switch quickly between apps. You'll also be able to view all of your recent documents so you can quickly get back to what you were working on.
One thing that's new is that Microsoft Search is built into it. Announced at Ignite this year, Microsoft Search combines internal searches with external searches, so it can search the web and Microsoft 365 at the same time. Finally, businesses will be able to tailor the app to their organizations, adding custom branding and such.
The new Office app will be available for Windows Insiders on the Fast ring today, and other Windows 10 users will get it soon. It works with Office 365, Office 2016, and Office 2019.