Patch Tuesday (April 2020 Updates) are now rolling out to all supported versions of Windows 10. The cumulative update with security fixes is rolling out with November 2019 Update, May 2019 Update and October 2018 Update. In April 2020, there are only security enhancements for the system, core components and other basic functions. If you don’t have the March optional updates applied, you’ll also get those fixes. You can open the Settings app and click on the Windows Update option to install the patches. If you own multiple PCs or if you want to patch the PCs manually, you can learn more about it here.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-cumulative-updates-kb4549951-and-kb4549949-released/