This line occurs during the climactic scene where Ron Burgundy (Will Ferrell) is anchoring a live news broadcast.
The line is meant to be humorous, mimicking a real-life news anchor's commands to the crew during a live broadcast. The phrase "Cameras to black" signals the end of the broadcast, while "Go camera Todd" is a direction to a specific camera operator. The final line, "Gator, shut it down," is a humorous call to end the entire production.