Liu SY, et al. - Since unfavorable clinical benefit to checkpoint inhibitors (CPIs) has been often shown by EGFR-mutated or ALK-rearranged non-small cell lung cancer (NSCLC) and not many reports exist with integrated analysis for understanding the fundamental mechanism of poor response to PD-1/PD-L1 inhibitors, researchers performed this retrospective analysis of the tumor microenvironment (TME) based on tumor PD-L1 expression and CD8 + T cells infiltration in these patients. They also assessed the prognostic power of TME subtypes on overall survival (OS). They detected a lower PD-L1 and CD8 co-expression level in TME in patients with EGFR mutations or ALK rearrangements, which could be accountable for poor response to CPIs. In EGFR-mutated or ALK-rearranged lung cancer, PD-L1 and CD8 co-expression was identified as a biomarker for poor prognosis with shorter OS.