iOS developer Guilherme Rambo has been poking around the new iOS 12 beta, and code contained within appears to confirm something that has been rumored multiple times: Face ID is coming to the iPad. Videos and screenshots tweeted by Rambo show that iOS 12 contains hidden references to Face ID on the iPad, including the setup UI and relevant section of the settings menu.
It's possible that these references could pertain to a feature that lets you unlock an iPad with an iPhone X, like how you can unlock a Mac with an Apple Watch, but that seems unlikely. The inclusion of the setup UI suggests it's for a device actually equipped with the Face ID sensors, which is something that has been credibly reported as planned for this year, so it seems safe to say an iPad with Face ID is on the way.
Apple has already announced that iOS 12 will go some way to unifying gesture control between the iPad and iPhone X, which has been a point of confusion for some of late. Control Center on the iPad is now accessed by swiping down from the top right of the screen while swiping up on the dock returns you to the home screen. The clock, meanwhile, has been moved from the top center to the top left, possibly presaging a display notch but more likely just aligning the two devices' software design.