Emerging tissue-, blood-, and host-based biomarkers of potential clinical benefit or therapeutic resistance to immune checkpoint inhibitors (ICIs) under evaluation in NSCLC. (PD-L1) Programmed death-ligand 1, (TILs) tumor-infiltrating lymphocytes, (TLS) tertiary lymphoid structures, (TMB) tumor mutation burden, (TCR) T-cell receptor, (ITH) intratumoral heterogeneity, (NKs) natural killer cells, (PD-1) programmed cell death protein 1, (NLR) neutrophil-to-lymphocyte ratio, (M:L) myeloid-to-lymphoid ratio, (PLR) platelet-to-lymphocyte ratio, (ctDNA) circulating tumor DNA, (bTMB) blood tumor mutation burden.