Play-By-Play Caster:

The PBP Caster is responsible for calling all the action in-game. The literal what is happening on screen.

Their primary goals are to drive energy and hype during the match while relaying key information to the audience.

Color Caster:

The Colour Caster is responsible for giving a professional, informed, and expert opinion on the match. These casters explain why things are happening. Their goals are less to do with information relay and more focused on expanding pin-point analysis.