What is the difference between black pepper sauce and black bean sauce?

Well, honey, black pepper sauce is made with, you guessed it, black pepper, giving it a spicy kick, while black bean sauce is made with fermented black beans, adding a savory and umami flavor. So, one's spicy, the other's savory - it's like comparing a fiery redhead to a mysterious brunette. Both delicious in their own way, just depends on what flavor you're in the mood for.