IDO1 and lung cancer: Since human lung cancer cells require several fold more of the mouse derived IL-1β to generate an IDO1/PD-L1 response that is seen with the human-derived IL-1β, further, studies need to be done in a syngeneic model such as genetically engineered mouse models (GEMMs), particularly to define whether IL-1 is present in mouse tumors, at what stage, and whether it contributes to tumor progression.