A cliffhanger is a way of telling a story where it stops at a really exciting or suspenseful part, and you don't know what is going to happen next. Just like when you're climbing a cliff, you have to stop at the top and figure out your next move.
When a show or book has a cliffhanger, it makes you feel like you really want to know what's going to happen next. It's a bit like when you're watching your favorite show and it finishes on a really exciting scene, and you can't wait to see what happens next week.
It's like when you stop in the middle of a game and have to wait before you can play again. You're left wondering and anticipating what will happen next, and really wanting to find out. But, just like when you climb a cliff, you have to be patient and wait until the next part of the story comes out.