Pega Robotics requires a Windows Operating System (usually Windows 10 is most common), so if you use MacOS, you'd need a VM to run Windows and Pega Robotics in. The applications you'd work with would need to run inside that VM as well.
Parallels wouldn't give you the ability to interrogate IOS or Android applications. While you might be able to launch them in a VM, you would not be able to interrogate any of their controls. There is currently no way to interrogate an IOS or Android application.
If you want to run Runtime or Studio on a Mac, Parallels would give you the ability to run a Windows Operating system and therefore install and use Pega Robotics, however the applications would be restricted to running within that Operating System.