It’s all right there in the headline! According to Variety, “Spoke Lane Entertainment and Mike the Pike Prods. have acquired film rights to George R.R. Martin’s werewolf novella ‘The Skin Trade.'” Here’s the premise:
Martin’s story is based on a female private investigator on the trail of a serial killer linked to an underground werewolf clan ruling the remains of a vibrant city devastated by a recession.
The novella was first published alongside work by Stephen King and Dan Simmons in a short horror anthology called Night Visions 5. It seems to be out of print, but there are some used copies available on Amazon