Senses
什么事/ 什麼事 What's the matter?
Used as a question to ask what is happening, what is up, or if something is wrong.
什么事/ 什麼事 no matter what
Used in a statement to mean whatever happens or regardless of what the issue is.
什么事/ 什麼事 what business it is of
Used in rhetorical questions to ask what business a situation is of a specific person (e.g., in the pattern 关 + {person} + shén me shì)