CD274 and melanoma: Several ICIs, mostly targeting the programmed cell death (PD)-L1/PD-1 (e.g. nivolumab, pembrolizumab) or the B7/cytotoxic T-lymphocyte-associated protein (CTLA)-4 (e.g. ipilimumab) pathway, have been approved either alone or in combination with e.g. chemotherapy for treatment of various cancer entities such as non-small cell lung cancer (NSCLC), malignant melanoma or urothelial carcinoma (3–5).