Early rumors suggested that we would see an all new Qualcomm chip in the Pixel 2 and Pixel 2 XL devices. The new chip was expected to be an updated version of the Snapdragon 835 which would have been a Snapdragon 836. This rumor makes sense as Qualcomm updated the Snapdragon 820 to the Snapdragon 821 for devices releasing in the fall. According to sources the Snapdragon 836 simply does not exists. This means that we will likely see the Snapdragon 835 in the new Pixel devices.
Apparently Qualcomm is still currently working on the next generation CPU, but we may not see it until early 2018. Another source has confirmed that Qualcomm is currently working on the Snapdragon 845 which will be featured in the Galaxy S9.
via XDA