An external GPU (eGPU)-powered Apple Display won't be among the things announced at WWDC 2016.
There'd been some speculation on Twitter and rumor reports about Apple possibly introducing a display with an integrated eGPU. Theory being, it would take some of the graphical processing overhead off MacBooks and/or facilitate a single-cable connection that could drive 5K. It sounds cool, but I asked around, and it's not happening at the keynote or any time in the immediate future.
So, scratch eGPU off your list for now, but keep your eyes locked to the keynote on Monday, June 13, for lots of other amazingly cool stuff.
We'll be there live to bring you back all the action!