Payload
What the truck can still carry after its own curb weight.
Payload is GVWR minus curb weight. It has to hold passengers, cargo in the cab and bed, and the tongue or pin weight of a trailer. Options and accessories already on the truck reduce the number on the door sticker.
Maximum payload and maximum towing are usually different configurations. A max-tow diesel is often heavier, so it has less payload than the gas truck advertised beside it.