Chainfire has done it! Yes he announced a few days back that he had achieved root on the Pixel and Pixel XL, but he now has a method which he is confident enough to release to the public! You need to have an unlocked bootloader. Once your bootloader is unlocked all you have to do is boot the "boot-to-root" file your phone will be rebooted and you will be rooted! This is one of the simpler root methods as it does not require you to flash a custom recovery first. This is also systemless root which means the system does not have to be modified. This should also mean that accepting OTA updates will be easier.
With root you will be able to bring back some missing features like double tap to wake, Google now on tap, and adaway. Some root apps like FlashFire will have to be updated to work with this version of SuperSU. It should be noted that the files for root should not be flashed in custom recovery. Head to the link below for instructions.
via XDA