I tried to get this working myself on my Pro X and came to the conclusion that the Global Protect VPN client must install a driver as part of the application so will not work unless/until Palo Alto releases a native ARM64 version since drivers cannot be emulated.
That said, if your company is licensed for mobile device VPN clients, there is a version of Global Protect in the Windows Store that installs just fine and builds on the built-in VPN functionality of Windows. I couldn't use it myself because my employer doesn't currently pay for this mobile device license, and for some reason they classified the store VPN client as a mobile device client.