ScoreCam cannot take video from an external camera such as a Mevo, GoPro, USB camera, or Continuity Camera. It records using the iPhone or iPad's own built-in cameras only.

It does work the other way around: you can send ScoreCam's camera, scoreboard, and audio into OBS Studio and use OBS to add graphics, intros, and scene transitions before broadcasting. See Can I use ScoreCam as a video source for OBS Studio? for the setup.