Therefore, researchers had not enough prior clinical experience to determine the appropriate conditions to perform this type of treatment, and the first phase I clinical trial performed in 12 patients with ccRCC applied a first-generation murine anti-CAIX CAR T (G250mAb) CD4TM-γ CAR, with daily infusions of 2 × 108 to 2 × 109 of anti-CAIX CAR T in association with IL-2 and with a maximum of 10 sequential infusions, obtaining disappointing results in terms of toxicity and efficacy. The gene discussed is CA9; the disease is nonpapillary renal cell carcinoma.