Someone fishing for info.
Just got a call claiming Apple detected hacking on my appleid. I am pretty sure it is somebody fishing for info. Let me know if you are getting lots of these inquiries. Their call back number was 855-929-0176
It is a scam! Apple does not make such calls to customers/users. Apple will only call a customers/user if they have previously arranged a call from Apple. Many get many scam calls. Virtually everyone has gotten at least one.