As such, it is possible that metformin efficacy in lung cancer is dependent upon specific patient and tumor characteristics, as is the case with targeted agents and immunotherapy agents which benefit only particular subgroups who present specific biomarkers (i.e., EGFR or ALK actionable mutations, as well as PD-L1 expression in tumor samples) [21,22,23,24]. Here, EGFR is linked to neoplasm.