CD274 and non-small cell lung carcinoma: Interestingly, a multifaceted role for the circ-CPA4/let-7 miRNA/PD-L1 axis in NSCLC was described by Hong et al., showing how circ-CPA4 promoted the production of tumoral-PD-L1+-EVs, which interacted with T cells to establish CD8+ T-cell inactivation, tumour immune escape and resistance to chemotherapy[79].