CA9 and nonpapillary renal cell carcinoma: In a subsequent article, the same humanized anti-CAIX/CD28 lentivector was adapted to secrete anti-PD-L1 IgG1 or IgG4 antibodies into the tumor milieu, which led to a remarkable reduction of T cell exhaustion and improved antitumor persistence in an orthotopic model of ccRCC in NSG mice.