PDCD1 and cancer: In the era of cancer immunotherapy, application of immune checkpoint blockade (ICB) targeting cytotoxic T lymphocyte–associated protein 4 (CTLA-4) and/or the programmed cell death 1 (PD-1/PD-L1) axis led to improved clinical outcomes in advanced clear cell renal cell carcinoma (ccRCC).1–3 Both combination of anti-PD-1 and anti-CTLA-44 as well as combined anti-PD-1/PD-L1 plus a tyrosine kinase inhibitor (TKI)5–8 are currently applied as first-line therapy in metastatic ccRCC.