In NSCLC, intratumoral taxa such as <i>Fusobacterium nucleatum</i> and <i>Bacteroides fragilis</i> promote progression and evasion via immune checkpoint modulation (PD-1/PD-L1), pro-inflammatory pathways (toll-like receptors and cytokines like interleukin-6/tumour necrosis factor-alpha), metabolic reprogramming (PI3K/AKT), and recruitment of suppressive cells (neutrophils and myeloid-derived suppressor cells). This evidence concerns the gene CD274 and non-small cell lung carcinoma.