Immunotherapies that use the immune system to eliminate tumor cells have shown substantial therapeutic effectiveness in several types of human malignancies. Several investigations have emphasized the importance of neoantigens in the recognition of cancer cells by innate T lymphocytes. The identification of neoantigens, which are altered proteins that are selectively produced in tumor cells and not in healthy cells, has resulted in the development of enhanced cancer vaccines. Neoantigen targeting may stimulate anti-tumor T-cell reactions to eliminate tumors while sparing healthy cells from harm. Significant progress in DNA sequencing and computational biology has enabled the identification and development of potent neoantigens for application as therapeutic cancer vaccines. Therapeutic customized vaccines that target neoantigens have demonstrated encouraging outcomes in the field of cancer therapy. Therefore, this study aims to introduce neoantigens and their use in cancer immunotherapy.