cue = indication. きかっけ
It comes from theatre Live actors often get "cues" from someone sitting behind the curtains to help them remember their lines.
Another example, an actor would leave the stage when he sees someone lift a sword.That would be an "exit cue". The phrase is now in general use.
You're from Japan. In Japanese etiquette, there are hundreds of "cues" きかっけ for this, that or the other. I think you get the picture.