As a new month begins, we're treated to a new set of security patches from Google for Android. Since today is the first Monday of the month, the company has published the associated bulletin and started rolling out over-the-air updates for the devices it still supports.
While security updates are important, the headline fix this month is one for the charging bug introduced with the Android 8.1 release, affecting the original Pixel XL. This should be gone after you apply the May update. Additionally, Google has baked in some multitouch detection improvements for all devices.
As always, the over-the-air rollout may take a few days to reach every device out there. If you're impatient you could manually check through Settings, it's a method that should work in getting you the update immediately. Alternatively, you can download a system image or full OTA zip file and flash that onto your phone.