CD274 and cancer: M2 macrophages also play a key role in metastasis by producing growth factors and proteolytic enzymes and triggering various inhibitory immune checkpoints in T cells.84 Higher frequencies of M2 TAMs are associated with poor prognosis in a range of cancers, including gastric and oesophageal cancers.85–87 In gastro-oesophageal cancer, increased M2 TAM infiltration is associated with increased PD-L1 expression and therefore may be associated with increased efficacy of ICIs.