Something that greatly differentiates the Fire TV Cube from the Fire TV 3 is the Cube's Micro USB port and the official support for expandability that comes with it.
Fire TV Stick Micro USB to RJ45 Ethernet Adapter with USB Power
Fire TV Cube: Details, Price, Release Date
Fire TV Stick vs. Fire TV Stick 4K vs. Fire TV Cube
All-New Fire TV Cube Unboxing and Review — Steemit
Bundle TV Stick 4K Cube Accessories - OTG Cable, USB
Roku vs Fire Stick: Which one is right for your streaming needs
Fire TV Cube review: Streamlined and speedy entertainment
How to Add Storage to Fire Stick OS 7/6/5 [A Full Guide
Fire TV Cube (2022) review: a streaming box with no equal