Imagine a house with all the furniture and people taken out — you're left with an empty shell that is easier to populate than just building a house from scratch, in the same way, decellularized dermis provides a scaffold that the body can try to populate with its own cells. The good thing about decellularized dermis is that it has a structure and composition that the human body is already used to — the body responds more favorably to what it is used to than what it isn't.