CA9 and renal cell carcinoma: The combination of the TKI sunitinib with another anti-CAIX CAR-T containing a CD8α transmembrane domain and the intracellular domains of 4-1BB and CD3ζ in a subcutaneous mouse lung metastasis model of human RCC has led to the survival of all mice at the end of the experiment (day 60), with decreased tumor burden compared to anti-CAIX CAR-T cells or sunitinib alone.