Programmed cell death protein 1 (PD-1) has been reported to be expressed in a tumor-promoting isoform of tumor-associated macrophages that are formed during tumor progression from pre-invasive to invasive adenocarcinoma, controlling the lymphocyte-depleted microenvironment of invasive tumors, and protecting the tumor cells in the solid histological components of tumors (Garcia et al., 2022). Here, PDCD1 is linked to neoplasm.