CTLA4 and renal cell carcinoma: The overexpression of CTLA4 due to promoter hypomethylation in RCC patients treated with ICI might be an independent factor for favorable outcomes (PFS: HR 1.94 (95% CI 1.09 to 3.44), p = 0.024; OS: HR 2.14 (95% CI 1.01 to 4.57), p = 0.048) (49).