what does that have to do with the price of tea in China
Meaning
what does that have to do with the price of tea in China?
(rhetorical question, colloquial) Used to indicate that a previous comment is irrelevant or non sequitur.
A: "I read that aliens built the Egyptian pyramids." – B: "What medications are you taking?" – A: "What does that have to do with the price of tea in China?"