The use of immunotherapy has completely changed how cancer is treated. Immune checkpoint blockade, bispecific antibodies, and adoptive T-cell transfer in particular have produced previously unheard-of clinical outcomes in solid cancers and hematological malignancies. Despite the fact that T cell-based immunotherapies have a variety of mechanisms at work, their ultimate objective is to induce the death of cancer cells. Unsurprisingly, one of the most important aspects of cancer biology is apoptosis evasion. Therefore, increasing cancer cells’ sensitivity to apoptosis is an important tactic for enhancing clinical outcomes in cancer immunotherapy. In fact, in addition to traits that encourage apoptosis in T cells and evade treatment, cancer cells are characterized by several intrinsic mechanisms to resist it. Apoptosis, however, has two sides: when it affects T cells, it serves as a crucial mechanism of failure for immunotherapies. This review will review the most recent efforts to improve T cell-based immunotherapies by raising apoptosis susceptibility in cancer cells, as well as the role of the hormone in regulating the survival of cytotoxic T lymphocytes in the tumor microenvironment and potential solutions.