AMPs	antimicrobial peptides
BM	brain metastasis
CDT	cytolethal distending toxin
CNF1	cytotoxic necrotizing factor 1
DCs	dendritic cells
DM	distant metastasis
EMT	Epithelial–mesenchymal transition
GLA	gut–lung axis
GPCRs	G protein-coupled receptors
ICIs	immune checkpoint inhibitors
MAITs	mucosal-associated invariant T cells
MIS	mucosal immune system
NGPs	next-generation probiotics
NK	natural killer
NSCLCs	non-small-cell lung cancers
PCs	plasma cells
PPs	Peyer’s patches
SCFAs	short-chain fatty acids
TLR	toll-like receptor
TNM	tumor-node-metastasis stage