Additionally, in EGFR mutant NSCLC, it is possible that atezolizumab is ineffective due to the fact that, first, previous studies indicated that the expression of PD-L1 is substantially lower in EGFR mutant tumors than in EGFR wild-type tumors, resulting in defective response to atezolizumab therapy in EGFR mutant patients (70, 71). This evidence concerns the gene CD274 and non-small cell lung carcinoma.