This post exists to collect my notes on displaying a USB webcam on the Raspberry Pi HDMI outputs. This is not the same as streaming the webcam (easy), and this is not for use with the Raspberry Pi camera module. This is specifically for USB UVC webcams.
This tutorial will walk you through setting up an ATEM Mini Pro kit you can ship to a remote location and then control from your studio. You can use this to ship a remote interview kit to someone where all they have to do is plug in a few connections and you'll be able to control everything remotely!