Microsoft is expected to roll out the Windows 10 May 2020 Update today, according to the information posted on a German support page. The Redmond giant has silently added Windows 10 version 2004 to the Windows lifecycle fact sheet, (via Deskmodder) which indicates that the major update will go live on May 27, 2020. Moreover, the end of service date for all editions is mentioned to be December 14, 2021. The Windows lifecycle fact sheet (shown below) is basically used to provide data on availability and end of service which is broken down by each Windows 10 edition.
(Edit) The site shows the information on the German language page but not on the English site. Here's a screenshot from the German language page:
... and our English translation
Once the Windows 10 May 2020 Update is generally available, it will go live in stages to users across the world. The progressive roll-out strategy helps Microsoft to ensure that everything is going smoothly. If Microsoft finds issues based on early feedback from users, the software giant can temporarily halt the release for impacted configurations.
Meanwhile, Microsoft will also release ISO files for people who want to perform a clean installation of the Windows 10 May 2020 Update on their PCs. In addition, once the rollout begins, you can use the Media Creation Tool in order to create bootable installation media from Microsoft’s official website. In case you missed, the Windows 10 version 2004 ISO files are already available for download via MSDN, and they should be available for everyone once Microsoft pushes the release button for the Windows 10 May 2020 Update.