CA9 and nonpapillary renal cell carcinoma: To improve the efficacy of G36-CD28ζ against ccRCC, Suarez et al. tested armored anti-CAIX G36 CAR-T cells secreting anti-programmed cell death ligand-1 (PD-L1) IgG1 or IgG4 mAb, which target PD-L1 positive ccRCC cells and block the PD-1/PD-L1 pathway.