We expect to see the official announcement of the Pixel 2 sometime next month. It looks like Google is already preparing for the launch of this device. They just uploaded a new "Data Transfer Toll" app to the Play Store. This seems to be a system app for the Pixel 2. There is currently a migration tool built into Android which allows you to transfer some data and apps from an older Android device to a newer Android device.
This new app will more than likely be an improved version which also has support for transferring apps and data from an iPhone. Their is one screenshot listed which appears to show data being transferred from an iPhone to a Pixel 2 XL. The screenshot showcasing the Pixel has already been removed from the listing and has been replaced with an image showing a Nexus 6P. This app should be preinstalled on the Pixel 2 and Pixel 2 XL.