CD274 and metastatic melanoma: BMS-936559 (MDX-1105) is a fully human IgG4 monoclonal antibody that inhibits binding between PDL-1 and its receptor; similarly, atezolizumab (MPDL3280A), durvalumab (MEDI4736), and avelumab (MSB0010718C) are three humanized IgG1 monoclonal antibodies with high affinities and specificities to PDL-1 that are already used in several clinical trials for metastatic melanoma (Li et al., 2016; Keilholz et al., 2019; Blank et al., 2021; Mao et al., 2022).