 Aberrant metabolite production in the TME, such as the pathway regulation by IDO, can affect T cell functions directly and indirectly via cells such as Treg cells.CD8 cells can be suppressed by B cells regulation of TAM phenotypes.Cancer-associated fibroblasts (CAFs) have multiple TME functions, in part through extracellular matrix (ECM)–mediated T cell trapping and CXCL12-regulated T cell exclusion.