Novel cellular immunotherapy with engineered T cells has improved cancer treatment and established therapeutic promises to prevent tumor formation in clinical studies. Due to certain restrictions and difficulties, CAR and TCR T-cells therapies were inadequate at points. CRISPR Cas9 genome-editing tool has significant potential for these two cell-based therapies. As a specialized gene-editing technique, CRISPR Cas9 is used to repair genetic alternations with minimal damage. It is used as an adjunct to immunotherapy to stimulate a more robust immune response. CRISPR has long outpaced other target-specific genome editing methods such as ZFNs and TALEN because of its high efficiency, competence in targeting, and stable operating conditions. CRISPR can overcome the two major drawbacks of universal CAR T cells: allorejection and graft-vs-host disease. TCR-based T cell treatment can reduce inappropriate binding between endogenous and transgenic TCR, resulting in a reduction of severe toxicity. The CAR and TCR T based cell therapies uphold an excellent future for tumor malignancies. This article has elucidated the administration of CRISPR Cas9 in novel cellular immunotherapy, CAR, and TCR T cell therapy. However, this article did not fail to observe this technology's ethical concerns, limitations, and challenges. Furthermore, the article compares CRISPR-mediated allogeneic CAR T cell to TCR-T cell therapy.