In "Pandora's box and "The Monkey's Paw" both themes are curiosity. In Pandora's box they show curiosity by Pandora opening the box when told not to. In The Monkeys Paw they show curiosity by holding and questioning the monkeys paw.
In both stories both of the main characters did something they weren't supposed to. Pandora wasn't supposed to open the box. In the Monkey's Paw they were not supposed to make bad wishes.
The characters both faced bad consequences. Pandora had let out bad spirits when opening the box. Mr/Mrs White's son died after they had made a wish.
The differences in the two stories is one's curousity was about a box and what would happen. Another's curiosity was about a wish.
In Pandora's box the karma was bad spirits. In The Monkeys paw the karma was the son dying. Both were consequences though.
In pandora's box they were warned not to open it. In monkeys paw they weren't warned, they had no clue their son would die.