You can unroot CyanogenMod running on the Nexus 4 & Pokemon Go will run just fine. You have to give the SuperSU app root privileges in order to unroot ironically, but it works just fine & you can always root your system from the bootloader in the future if it turns out that you need root for some reason.

There’s an app in the Play Store that runs the tests the Google library that Niantic is using to check whether a phone is rooted or not (it’s the same tests used by the Google Pay infrastructure IIRC).