CD274 and Merkel cell skin cancer: Recently, ICIs have become the new standard first-line treatment for patients with metastatic MCC, as they have been shown to improve OS compared to platinum-etoposide chemotherapy [91,92,93,94,95], but only avelumab, a fully human monoclonal antibody directed against the programmed death ligand 1 (PD-L1), received FDA and EMA approval, following the results of the JAVELIN Merkel 200 trial.