The article discusses the immunological aspects of cancer chemotherapy and how conventional cancer treatments, including chemotherapy and radiotherapy, can influence the immune system. It highlights that the immune system plays a crucial role in the antitumor effects of these treatments. The article reviews the immunological aspects of conventional cancer treatments and suggests that future cancer treatments may benefit from combined chemo- and immunotherapies. Cancer is not solely a genetic disease but also influenced by the tumor microenvironment, stroma, and immunity. Tumor cells must overcome both intrinsic and extrinsic barriers to oncogenesis, and immune control is essential for their progression. The article notes that the immune system can affect tumor progression in humans, as evidenced by the increased incidence of some solid tumors in immunosuppressed patients and the positive prognostic impact of tumor-specific cytotoxic T lymphocytes. Historically, cancer drug discovery has overlooked the possibility that immune reactions might contribute to treatment efficacy. However, accumulating evidence indicates that cytotoxic drugs can affect the immune system, contributing to tumor regression. The article summarizes current knowledge on the contribution of the immune system to conventional cancer therapies, noting that conventional therapies can elicit specific cellular responses that render tumor-cell death immunogenic or stimulate the immune system through various mechanisms. The article also discusses the immunosuppressive side effects of chemotherapeutic agents, such as those that impair T-cell functions, and the potential for these effects to hinder immune responses against tumors. It highlights the importance of understanding the immune system's role in cancer treatment and the need to develop strategies that enhance immune responses to control residual disease. The article explores the theoretical bases for antagonistic effects, including the role of the immune system in tumor progression and the potential for immunostimulatory effects of certain chemotherapeutic agents. It discusses the mechanisms by which chemotherapy can induce immunogenic cell death and the importance of the immune system in recognizing and eliminating dying tumor cells. The article also covers the immunological effects of various chemotherapeutic agents, including their ability to stimulate immune responses, such as the activation of NK cells and T cells, and the potential for these agents to enhance the effectiveness of immunotherapies. It highlights the importance of understanding the complex interactions between the immune system and cancer treatments to develop more effective therapeutic strategies.The article discusses the immunological aspects of cancer chemotherapy and how conventional cancer treatments, including chemotherapy and radiotherapy, can influence the immune system. It highlights that the immune system plays a crucial role in the antitumor effects of these treatments. The article reviews the immunological aspects of conventional cancer treatments and suggests that future cancer treatments may benefit from combined chemo- and immunotherapies. Cancer is not solely a genetic disease but also influenced by the tumor microenvironment, stroma, and immunity. Tumor cells must overcome both intrinsic and extrinsic barriers to oncogenesis, and immune control is essential for their progression. The article notes that the immune system can affect tumor progression in humans, as evidenced by the increased incidence of some solid tumors in immunosuppressed patients and the positive prognostic impact of tumor-specific cytotoxic T lymphocytes. Historically, cancer drug discovery has overlooked the possibility that immune reactions might contribute to treatment efficacy. However, accumulating evidence indicates that cytotoxic drugs can affect the immune system, contributing to tumor regression. The article summarizes current knowledge on the contribution of the immune system to conventional cancer therapies, noting that conventional therapies can elicit specific cellular responses that render tumor-cell death immunogenic or stimulate the immune system through various mechanisms. The article also discusses the immunosuppressive side effects of chemotherapeutic agents, such as those that impair T-cell functions, and the potential for these effects to hinder immune responses against tumors. It highlights the importance of understanding the immune system's role in cancer treatment and the need to develop strategies that enhance immune responses to control residual disease. The article explores the theoretical bases for antagonistic effects, including the role of the immune system in tumor progression and the potential for immunostimulatory effects of certain chemotherapeutic agents. It discusses the mechanisms by which chemotherapy can induce immunogenic cell death and the importance of the immune system in recognizing and eliminating dying tumor cells. The article also covers the immunological effects of various chemotherapeutic agents, including their ability to stimulate immune responses, such as the activation of NK cells and T cells, and the potential for these agents to enhance the effectiveness of immunotherapies. It highlights the importance of understanding the complex interactions between the immune system and cancer treatments to develop more effective therapeutic strategies.