So, you know how there are different kinds of Christians, right? Well, Catholics and Protestants are two of those kinds.
A long, long time ago, there was only one kind of Christian - the Catholic kind. But then, a man named Martin Luther disagreed with some of the things that the Catholic Church was teaching and doing. He wanted to make some changes, but the Catholic Church didn't want to listen to him. So, he and some other people broke away from the Catholic Church and started their own kind of Christianity. They were called Protestants because they were "protesting" against the Catholic Church.
Nowadays, Catholics and Protestants are still different, but they try to get along better. They realize that they both believe in Jesus and the Bible, even if they have some differences in the way they worship and think about things.
People from both groups are working to build better relationships, talk to each other, and understand each other's beliefs. They might even have joint worship services or events together. They might still disagree on some things, but they try to be respectful and kind to each other.