PDCD1 and cancer: The study found RCC is immune-sensitive cancer that widely expresses PD-L1, a factor that is associated with poor prognosis.[28–30] Relative to inhibitor of mammalian target of rapamycin (mTOR, a major breakthrough in ccRCC treatment), the PD-1 blocker nivolumab was found to improve OS (25 months vs 19.6 months).[31,32] Novel immune checkpoint inhibitors are also being evaluated in RCC.