PDCD1 and nonpapillary renal cell carcinoma: In an orthotopic model of human ccRCC in NSG mice both anti-CAIX/anti-PD-L1 IgG1 and IgG4 CAR T cells were able to revert T cell exhaustion as evidenced by downregulation of exhaustion markers PD-1, TIM-3 and LAG-3 in the TILs.