Okay, so let's say you and your friends are all playing together and you accidentally break a toy. Your friend's mom might get mad and want to punish you for breaking the toy. But, if your mom or dad tell her that you are immune from punishment, that means you can't be punished for breaking the toy.
Now, when we talk about immunity from prosecution, it's like the same thing, but for grown-ups when they do something wrong. Sometimes, people who work for the government, like the police, the President or the Prime Minister, or even doctors who work for the government, might do something wrong or illegal. But, if they have immunity from prosecution, it means they can't be punished for the wrong thing they did.
This is because they have special protection that means they can't be arrested, put in jail or face any other kind of punishment. This way, they can do their job without worrying that they might get in trouble for doing it. The idea behind immunity from prosecution is that it allows these government officials to do their job effectively without being afraid of being punished for doing something that might be necessary, but technically illegal.
However, immunity from prosecution is not always fair. Sometimes, government officials might abuse their power and do things that are illegal or unethical without consequences. That's why, some people believe that we should limit immunity from prosecution, so that everyone is held accountable for their actions.