EGFR and neoplasm: However, despite several preclinical studies showing a consistent positive correlation between EGFR mutation and programmed cell death ligand 1 (PD-L1) expression, both in cell lines [15,16] and in patients’ tissue samples [17,18], EGFR mutated tumours consistently showed no response to anti-PD-1/anti-PD-L1 treatment across most of the clinical trials.