EGFR and lung adenocarcinoma: , demonstrated that EGFR-mutant lung adenocarcinoma patients with PD-L1≧50% had a higher chance of primary resistance to EGFR-TKI than patients with PD-L1 1 to 49% and patients with PD-L1 < 1% (44.4% versus 2.6% versus 6.3%, respectively; p < 0.001)20.