It is always important to stay current on events in your industry. If you have not heard about the specific case you are asked about, don't worry! You can simply respond that you haven't had the time to dig into the case. If you know of another recent case, transition into talking about that ruling to show that you are following important developments in your desired practice area. If you have heard about the case, simply answer honestly. If you know how certain judges typically rule and this case matches/veers away from their usual result, acknowledging this in your answer shows an even more sophisticated understanding to the hiring partner.