IFNB1 and Merkel cell skin cancer: A 59-year-old man presented with symptomatic, widely metastatic MCPyV-positive MCC that progressed through > 5 therapeutic regimens, including surgery, radiotherapy (RT), cytotoxic chemotherapy, intra-tumoral (IT) interferon-beta, IT interleukin (IL)-12, somatostatin analogues, and adoptive T cell therapy (ACT) with MCPyV-specific T cells plus pembrolizumab.