What's (up) with (someone)?
Why is someone so upset or acting in such an unusual way? What's with Jeff? He just screamed at me and stormed out of the room. I wonder what's up with Sarah—she's been avoiding me for days now.
what’s with somebody?
(American English, spoken) used to ask why somebody is behaving in a strange way: What’s with you? You haven’t said a single word all morning.