Does anybody have any experience subletting a house in the Chicago area? I am not talking about short term AirBnb style of subletting. I recently posed the question to a potential landlord and he replied that every person in the house needs to be on the lease. Is this because of Illinois law or possibly his own landlord insurance policy that prohibits subletting?

I am from Chicago.  I doubt that is law, but more of a landlord rule / request.   Subletting residential is somewhat rare.   In my leases, I forbid it.  I want to screen my tenants and not let a non-professional pick a tenant that can be a nightmare for me.