Issue installing BootCamp drivers for Windows 10

I had the same problem as well. The issue seems to be that the Bootcamp software is looking for the correct Realtek drivers, but can't find them so it just hangs. To fix it, manually install the drivers from Realtek while the Bootcamp setup is running. Then, go to Task Manager, find the Setup process, right click and press Go to details. Then find the RealtekSetup.exe process and kill that. Bootcamp setup will now skip that step and continue installing the rest of the drivers. And since you downloaded the realtek drivers manually, you now have those as well.

For more info see this thread on apple discussion forms.

According to @Pi, it is unnecessary to download the Realtek drivers. Just kill the RealtekSetup.exe process, let the installation of the rest of the drivers complete, and then run this RealtekSetup.exe process from list of software included in the Bootcamp drivers. You can find this executable at /BootCamp/Drivers/Realtek/RealtekProcess.exe.