Abstract: Personalized precision medicine is vital part of tumor immunotherapy. Neoantigen is kind of epitope peptides on major histocompatibility complex(MHC) which is specially located on surface of tumor cells. They are a kind of antigenic peptides with specific amino acid sequence variation, which are encoded, transcribed and translated by mutated somatic genes. There are a thousand Hamlets in a thousand people's eyes, so as the tumor mutations. Neoantigen is one of the important ways to realize "personalized" therapy. Neoantigen therapy is a supplement to represented by PD-1/PD-L1 antibody and CAR-T. This article reviews the discovery process of neoantigen, the application of neoantigen vaccine in tumor immunotherapy and clinical trials.