I've seen people passing their laptop dGPUs yet I haven't been successful because of a lot of reasons, mainly extracting the vbios (that somehow some laptop users can do but I cannot, and I wasn't the only one) and having it UEFI (mine wasn't which is weird as it's a SKL laptop) and they said that some Muxed laptops are easy to deal with. And after a while with the help of some people in the hackintosh discord server, we made an even larger layout list of display outputs we stumbled upon while helping some new users with their laptops (thanks /u/dhinakg):

My laptop (Thinkpad P50) happened to be something like the Macbooks where there is a mux between the iGPU and dGPU to the eDP (this has been confirmed with my laptop's schematics).
Great! So you can just pass the dGPU and see stuff on either the display