Calling it now: Lady Sofia hired Jhin

The thing is that as far as we know,Jhin isn't an assassin for hire. He is an assassin that works for the ionian government.

Even if Sophia had the means of knowing about Jhin and contacting the Ionian government, I doubt they would lend him to her. They are kinda using him as defense against Noxus. Sure, he might possibly come on his own will if she contacted him directly, but I'm willing to bet that would be a whole lot harder to do. I find it more likely Lady Sophia would try to hire Jinx who's been terrorizing Piltover and keeping out of the Sheriffs reach; however she would most likely just shoot her in the face.

However making a rivalry between Jhin and Camille could be pretty interesting. I just don't see it happening.

Maybe the Ionian cabal have "loaned" Jhin to some people in Piltover.