While PRRs are highly expressed by APC lineages that are known to infiltrate the TME, including conventional myeloid dendritic cells (cDC), plasmacytoid dendritic cells (pDC), and tumour associated macrophages (TAMs), they can also be expressed on CD8+ and CD4+ T cells, regulatory T cells (Treg), and B cells [32]. Here, CD4 is linked to neoplasm.