PDCD1 and melanoma: Concerning the relationship between the ROS-related signature and the primary/acquired resistance to immunotherapy, we analyzed the GSE91016 dataset in which melanoma patients were treated with anti-PD-1 and anti-CTLA4 therapy 42, and the RNA-seq data of pre- and on-treatment of tissue samples were available, enabling us to investigate the changes of the ROS-related signature upon immunotherapy.