PDCD1 and melanoma: Patients with active brain metastases were excluded from most of the clinical studies, despite the fact that anti-programmed cell death protein 1 (anti-PD1) and anti-cytotoxic T-lymphocyte antigen 4 (anti-CTLA4) immunotherapies and mitogen-activated protein kinase-targeted (MAPK-targeted) treatments have been extensively employed in the treatment of systemic metastases from melanoma (Eroglu et al., 2019).