Cynics point out that a cure for cancer has been "around the corner" for the last 50 years. Nevertheless, the recent convergence of deep DNA, RNA, and proteomic technologies with enhanced understanding of the nuances of the adaptive immune system has generated great optimism amongst researchers. The extraordinary heterogeneity of various cancers, once thought to be a major therapeutic hurdle, may now be bypassed via "personalized" vaccine treatments. Specifically, these treatments involve the identification of MHC-bound peptides that are unique to a patient's cancer (neoantigens), followed by immunization with peptides, RNA, or DNA that encodes these neoantigens via various delivery systems, thus amplifying the immune system's response to the particular cancer. Such approaches have shown dramatic results in animal studies. Not surprisingly, then, the field of neoantigen-based immunotherapy has advanced at a spectacular rate, necessitating that interested individuals stay apprised of recent developments. Following an introduction to the subject, we thus focus on aspects that are particularly fast-moving; the cellular sources of neoantigens, which are surprisingly diverse, the tools that are used for their identification, and the status of the numerous clinical trials that are now being conducted.