You're the doctor

You're the doctor. (You are in a position to tell me what to do; I yield to you and your knowledge of this matter)
≅ Тебе виднее.
≅ Тебе лучше знать;
≅ Как скажешь.
≅ Хозяин – барин.

Usage note
Usually jocular ( the person being addressed is most likely not a physician.)

Example 1:
Bill: Eat your dinner, then you'll feel more like playing ball. Get some energy!
Tom: Okay, you're the doctor.
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

Example 2:
Teacher: You'd better study the first two chapters more thoroughly.
Bob: You're the doctor.
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)