CD274 and neoplasm: To compare the immune escape capability of tumour cells among EGFR-TKI sensitive and resistant NSCLC in vivo, we generated EGFR-TKI sensitive and resistant NSCLC cells with PD-L1 gene deletion, and its control cells (PC-9PD-L1-, PC-9RPD-L1-, PC-9PD-L1+, and PC-9RPD-L1+) using the CRISPR-Cas9 knockout lentivirus.