Virtualization and cloud services are nothing new, most servers and software suites these days are based on that. For business users, a virtual OS already exists, but for consumers and end-users this is a relatively new thing.
https://www.guru3d.com/news-story/microsoft-is-working-on-virtual-windows-os-via-azure-cloud-for-2021.html
https://www.guru3d.com/news-story/microsoft-is-working-on-virtual-windows-os-via-azure-cloud-for-2021.html