VTCN1 and neoplasm: Moreover, we were unable to identify a reciprocal loss-of-function model (i.e., B7-H4-KO) to test necessity of B7-H4 expression for anti-PD-L1 resistance; however, given that breaks in the tumor immunity cycle can exist at nearly any point in the path, identifying a model that innately expresses B7-H4 in the tumor compartment, and wherein this feature is the sole effector of resistance to anti-PD-L1 is far less likely given the general paucity of models in the field.