Possible meanings are 1) by saying this, Jesus implied that he is the King of the Jews. AT: "Yes, as you said, I am" or "Yes. It is as you said" or 2) by saying this, Jesus was saying that Pilate, not Jesus, was the one calling him the King of the Jews. AT: "You yourself have said so" (See: [[rc://en/ta/man/translate/figs-explicit]])
Pilate asks this question because he is surprised that Jesus remains silent. AT: "I am surprised that you do not answer these people who accuse you of doing bad things!" (See: [[rc://en/ta/man/translate/figs-rquestion]])