Immune T cells can kill cancer cells. Cancer vaccines function by increasing the number of immune T cells. There are exceedingly strict biologic limits imposed on the immune system to prevent excessive T-cell activation and expansion. The same biological restrictions limit cancer vaccines. Immunotherapeutic agents that circumvent the biological restrictions have been invented and formulated, including (i) dendritic cell activators and growth factors, (ii) vaccine adjuvants, (iii) T-cell stimulators and growth factors, (iv) immune checkpoint inhibitors, and (v) agents to neutralize or inhibit suppressive cells, cytokines, and enzymes. Few of these agents are broadly available for the development of effective multiple component regimens. The major problem facing immunotherapy today is a lack of broad availability of agents already in existence. The National Cancer Institute has developed a well-vetted ranked list of agents with high potential to serve as immunotherapeutic drugs. This review focuses on 12 of the agents, all with proven ability to augment T-cell responses. Alone, each has little chance of making substantial inroads into cancer therapy. In combinations dictated by biology, the agents are overwhelmingly likely to have an impact. Future availability of these agents for development of innovative combination cancer therapy regimens will provide a benchmark for the resolve of the national cancer therapy translational research enterprise.