This is a great (and inexpensive) HDMI capture card. Giving you a 1080p signal from any DSLR or Mirrorless camera that can output a clean HDMI feed! This is great to up your live stream quality!
A more expensive 4k alternative would be the Elgato CamLink 4k.
To connect up between 4 and 8 HDMI devices to your computer or live stream directly, you should take a look at the ATEM Mini Lineup.