HAVCR2 and neoplasm: Effector T cells in the tumor microenvironment (TME) exhibit high levels of expression of multiple inhibitory receptors, such as PD-1, T cell immunoglobulin and mucin-containing protein 3 (TIM3), T cell immune receptors with Ig and ITIM structural domains (TIGIT), and LAG3 [37] (lymphocyte activation 3), which are considered markers of a dysfunctional state widely known as T-cell depletion [38].