The term is easy to understand cross-fire, but how is crossfire formed and how can it be perfect in such a way that instant trades can happen?
From what I can understand without any clue of forming crossfires, you will know that you are in crossfire when you can see your teammate in your POV/is very near and they can see you in their POV/is very near along with the target where both are looking. Now this doesnt means that ones should always be at 90° of angle. How will you form a crossfire?