What happens if the plaintiff and/or the defendant dies before, during or after a lawsuit?

It may seem like an odd question, but I’m only curious.

Say either the plaintiff or defendant dies before the court date. What happens to the case?

What happens if they die in the middle of the case? Or right after a judgement has been made?

Would it all depend on the state or the circumstances of the lawsuit? This would be for a left turn car accident.