The PEB is not a kernel mode data structure itself. It resides in the application mode address space of the process that it relates to
https://en.wikipedia.org/wiki/Process_Environment_Block
DEBUG AND ANTI-DEBUG TIPS AND TRICKS EXPLORING PEB STRUCTURE:
https://rvsec0n.wordpress.com/2019/09/13/routines-utilizing-tebs-and-pebs/
on x64dbg you can press ctrl + g to open the “Enter expression to follow…” and type:
peb()
or
ted()