Several major strategies targeting TAMs have been applied for cancer treatment so far: inhibition of TAMs recruitment (CCL2/CCR2 axis, CCL5/CCR5 axis, etc.), depletion of TAMs [Colony-stimulating factor 1 (CSF1)/CSF1R axis, etc.], induction of M1 macrophage polarization [CD47/Signal regulatory protein alpha (SIRPα) axis, CD40/CD40L, etc.] and enhancement of macrophage-mediated phagocytosis [PD-1/PD-L1axis, MHC-1/leukocyte immunoglobulin like receptor B1 (LILRB1), etc.] (Anfray et al., 2019; Zhou, Liu and Huang 2021b). Here, PDCD1 is linked to cancer.