Scott Lynch has named Leiber as the writer he is working from, and the books show it before he says it. Camorr is Lankhmar: a wet, stratified, canal-cut city with a thieves' guild that is a real institution, gods with functioning temples, and an underworld that has rules and enforces them. Locke and Jean are Fafhrd and the Gray Mouser with the proportions kept, the small clever one and the large one, working as a pair, taking jobs rather than quests. The whole sub-genre of the caper fantasy descends from Leiber, which is what makes this a foundational claim rather than a resemblance.