Google has started rolling out the May 2020 security patch for all the compatible and supported Pixel phones. This includes the Pixel 4 series, the Pixel 3a, and the Pixel 2 and Pixel 3 XL.
The May 2020 security patch fixes a number of security vulnerabilities, though this time around, Google has not introduced any functional changes on the Pixels with this update. You can find all the security patches fixed in the May 2020 Android security bulletin.
If you own a Pixel phone, you can go to Settings and check for updates to download the latest security patch. Google has also uploaded the factory images and OTA files on its website so you can download the update from there and sideload it manually on your device as well. If you decide to manually sideload the May 2020 patch, make sure to download the correct build for your device. The files appended with "A3" are meant for Taiwan carriers, while the "B3" builds are for the rest of the world.
Samsung has already beaten Google in rolling out the May 2020 security patch for some of its flagship devices like the Galaxy S20 and Galaxy Fold.