When people complained about the new MacBook Pros using USB-C Thunderbolt 3 ports instead of old USB ports, I kept saying that they were missing something big. These new ports are not just ports, they are like expansion slots. Expansion slots just like opening up a desktop and inserting a card. And since then a few eGPU products have come out that let you do just that kind of thing.
Starting last week, Apple is carrying a product from Blackmagic that is a $699 eGPU. So you plug this into your MacBook Pro and now your graphics processing is running at the speed of a desktop, not a laptop. For graphics pros dealing with images, videos, 3D modeling and gaming, this is a nice alternative to having a separate desktop machine just to get the most intense work done.
Both MacRumors and Apple Insider seem to have gotten review units of this eGPU. There are other eGPU solutions that work with Thunderbolt 3, some really expensive that even let you swap out the cards inside. But this one is notable because Apple is promoting it and selling it in their store.