CTLA4 and renal cell carcinoma: In view of the current research showing that the combined use of PD-1 inhibitors (nivolumab) and CTLA4 inhibitors (ipilimumab) brings significant survival advantages for patients with renal cell carcinoma [38], the strong correlation between RCC1 and the two checkpoints indicates that it may be a powerful immunotherapy marker for KICH and KIRC.