The article discusses the immunosuppressive strategies employed by tumors to evade immune responses, including impaired antigen presentation, activation of negative costimulatory signals, and secretion of immunosuppressive and pro-apoptotic factors. It highlights the role of regulatory cell populations such as regulatory T cells, NKT cells, and specific dendritic cell subsets in maintaining this immunosuppressive network. The authors emphasize the importance of understanding these mechanisms to develop effective immunotherapy strategies, such as blocking immunosuppressive pathways and removing inhibitory signals. The article also reviews recent findings on cancer immunoeediting, a concept that integrates tumor-immune escape with the immunoediting theory, and discusses the induction of T-cell tolerance by malignant cells, particularly CD4+ and CD8+ T-cells. Finally, it explores various immunosuppressive strategies used by tumors, including abnormalities in antigen presentation, defects in proximal TCR signaling, secretion of immunoregulatory cytokines, negative costimulatory pathways, and modulation of tryptophan catabolism. The article concludes by addressing the "tumor counterattack" hypothesis, which suggests that cancer cells may use death receptor ligands to eliminate effector T-cells, and the role of regulatory T cells in establishing tumor-immune privilege.The article discusses the immunosuppressive strategies employed by tumors to evade immune responses, including impaired antigen presentation, activation of negative costimulatory signals, and secretion of immunosuppressive and pro-apoptotic factors. It highlights the role of regulatory cell populations such as regulatory T cells, NKT cells, and specific dendritic cell subsets in maintaining this immunosuppressive network. The authors emphasize the importance of understanding these mechanisms to develop effective immunotherapy strategies, such as blocking immunosuppressive pathways and removing inhibitory signals. The article also reviews recent findings on cancer immunoeediting, a concept that integrates tumor-immune escape with the immunoediting theory, and discusses the induction of T-cell tolerance by malignant cells, particularly CD4+ and CD8+ T-cells. Finally, it explores various immunosuppressive strategies used by tumors, including abnormalities in antigen presentation, defects in proximal TCR signaling, secretion of immunoregulatory cytokines, negative costimulatory pathways, and modulation of tryptophan catabolism. The article concludes by addressing the "tumor counterattack" hypothesis, which suggests that cancer cells may use death receptor ligands to eliminate effector T-cells, and the role of regulatory T cells in establishing tumor-immune privilege.