PDCD1 and melanoma: In the present study, we conducted multi-omics experiments, including proteomics and targeted quantification of mRNA expression performed on clinically available formalin-fixed, paraffin-embedded (FFPE) tissues from a set of melanoma patients who were considered to be good responders or poor responders defined by progression-free survival (PFS) after anti-PD-1 therapy for 1 year.