The article discusses the role of immunosurveillance in cancer development and the mechanisms by which cancer cells evade this surveillance. Immunosurveillance involves the recognition and destruction of cancer cells by the immune system, but cancer cells can avoid this process through immunoselection (selecting non-immunogenic tumor variants) and immunosubversion (active suppression of the immune response). The authors highlight that early stages of carcinogenesis are associated with cell-intrinsic barriers that stimulate an antitumorigenic immune response, while overt tumor development correlates with changes in tumor cell immunogenicity. They also emphasize the importance of using immunogenic chemotherapy to re-establish antitumorigenic immune responses for successful cancer treatment. The article reviews recent studies linking cell-intrinsic and cell-extrinsic mechanisms of tumor suppression, and suggests that avoidance of immunosurveillance might be the seventh hallmark of cancer, mechanistically linked to the six established cell-intrinsic characteristics of cancer cells.The article discusses the role of immunosurveillance in cancer development and the mechanisms by which cancer cells evade this surveillance. Immunosurveillance involves the recognition and destruction of cancer cells by the immune system, but cancer cells can avoid this process through immunoselection (selecting non-immunogenic tumor variants) and immunosubversion (active suppression of the immune response). The authors highlight that early stages of carcinogenesis are associated with cell-intrinsic barriers that stimulate an antitumorigenic immune response, while overt tumor development correlates with changes in tumor cell immunogenicity. They also emphasize the importance of using immunogenic chemotherapy to re-establish antitumorigenic immune responses for successful cancer treatment. The article reviews recent studies linking cell-intrinsic and cell-extrinsic mechanisms of tumor suppression, and suggests that avoidance of immunosurveillance might be the seventh hallmark of cancer, mechanistically linked to the six established cell-intrinsic characteristics of cancer cells.