In the tumor microenvironment (TME), some tumor and regulatory immune cells, such as regulatory T cells (Tregs) [119–122], myeloid-derived suppressor cells (MDSCs) [123–128], tumor-associated macrophages (TAMs) [129–131], immature dendritic cells (iDCs) [132, 133] have the ability to generate inhibitory molecules (like TIM3 [134–136], TIGIT [137, 138] and VISTA [139]), which can bind receptors on immune cells (NK cells, lymphocytes, etc.), reducing the toxicity of immune responses and thus contributing to immune escape. The gene discussed is HAVCR2; the disease is neoplasm.