Epidermal growth factor receptor tyrosine kinase inhibitor remodels tumor microenvironment by upregulating LAG-3 in advanced non-small-cell lung cancer

•LAG-3 expression was significantly upregulated after EGFR-TKI treatment.•L858R tumors had more infiltration of exhausted T cells compared to 19DEL tumors.•Tumors with less baseline infiltration of exhausted T cells were more likely to acquire T790 M after TKI treatment.•PD-1, TIM-3, or LAG-3 positivity were significantly associated with inferior PFS to first‐line EGFR-TKI.