With the 300-Euro Acer Graphics Dock you can add a GTX 960 M to any USB-C port that supports Thunderbolt. There's also USB PD (power) pass-through.
(Updated to replace GTX 940M error.)
Note there are two DisplayPorts, an HDMI and Gigabit ethernet on the rear of this unit. Apologies for the incorrect and incomplete information.
The Acer Graphics dock is actively cooled (fan.)
The Acer Graphics Dock will be available at the end of April (Germany) and will cost 300 Euro inclusive local taxes (Germany.)
This does look like a good graphics dock for making playing games faster, and more enjoyable on slower Windows tablets, and laptops which usually use slower onboard Intel graphics chips.
I like that the dock is easy to connect to a Windows laptop, or tablet with a USB-C or Thunderbolt cable.