How do you get the black cat mission?

Excuse me, could you please clarify how exactly one goes about acquiring the so-called "black cat mission"? I understand it's a task or assignment of some sort, but the specifics seem a bit vague. Could you provide more insight into the process of obtaining this mission, and perhaps any prerequisites or requirements that need to be met in order to embark on it? I'm quite intrigued and would appreciate any information you can offer.