CA9 and neoplasm: To assess the potential liver toxicity induced by the on-target off-tumor effect of anti-CAIX CAR T cells in the biliary duct, we analyzed the infiltration of CD3 cells in the liver by immunohistochemistry (Figure 5A,B); however, no statistical differences in the infiltration of anti-CAIX CAR T cells in the hepatic parenchyma among the groups were found after image quantification.