It is not good to keep a cat and the litter box overnight, because the litter box is not clean and sanitary. Cats staying in it for a night are easily infected with skin diseases or other diseases, and there is no food and water. They may also be very hungry, may bark all night, and may eat cat litter. It is best not to keep the cat and the litter box together. If you want to train the cat to defecate in the litter box, you can put its poop in the litter box, so that the cat will defecate in the litter box when it smells the smell.