Materials and methods: Formalin-fixed, paraffin-embedded (FFPE) pre-treatment tumor biopsies expressing PD-L1 were derived from 13 RCC patients treated on four clinical trials of nivolumab (anti-PD-1) monotherapy at a single institution [4 responders (R), 9 non-responders (NR); RECIST]. Here, PDCD1 is linked to renal cell carcinoma.