○ EGFR-mutant tumors with acquired resistance:○ Displayed a mesenchymal phenotype.○ Showed significantly increased IL-6 secretion.○ In EGFR-mutant GEMMs:○ Depleting IL-6:○ Enhanced activation of infiltrating natural killer (NK) and T-cell subpopulations.○ Reduced immunosuppressive regulatory T and Th17 cell populations.○ IL-6 inhibition in cell culture:○ Increased NK- and T cell-mediated killing of human osimertinib-resistant EGFR- mutant NSCLC tumor cells.○ IL-6 blockade sensitization:○ Sensitized EGFR-mutant GEMM tumors to PD-1 inhibitors.○ Increased tumor-infiltrating IFNγ+ CD8+ T cells. This evidence concerns the gene PDCD1 and neoplasm.