PDCD1 and metastatic melanoma: To further validate the immunotherapy resistance of EIC, we calculated the enrichment score of 167 exhausted immune classifier genes on the RNAseq data of 28 metastatic melanoma patients (GEO: GSE78220) treated with anti-PD-1 [18] and 497 LUSC patients of all tumour stages from TCGA (Project ID: TCGA LUSC, dbGaP Study Accession: phs000178) [14].