However, unlike the efficacy reported in patients with melanoma, the therapeutic response of anti-PD-1/PD-L1 mAbs in patients with mCRC is very different between mismatch repair-deficient (dMMR)/microsatellite-instability-high (MSI-H) tumors and mismatch repair-proficient (pMMR)/microsatellite-instability-low (MSI-L) or microsatellite-stability (MSS) tumors (11, 15–18). The gene discussed is CD274; the disease is melanoma.