Chimeric antigen receptor natural killer (CAR-NK) cells demonstrate significantly reduced cytokine release syndrome and neurotoxicity compared to CAR-T therapies, while maintaining efficacy against hematological malignancies, solid tumors, and autoimmune conditions. These engineered immune cells can be derived from multiple sources including peripheral blood, cord blood, and induced pluripotent stem cells, enabling standardized manufacturing protocols. The therapeutic advancement represents a meaningful evolution in cellular immunotherapy by addressing two critical limitations that have constrained CAR-T adoption: severe inflammatory side effects and the need for patient-specific cell harvesting. Unlike CAR-T cells, which require complex autologous manufacturing, CAR-NK platforms could enable universal donor products with predictable dosing and immediate availability. This "off-the-shelf" capability particularly matters for patients with rapidly progressing cancers who cannot wait weeks for personalized cell production. However, current CAR-NK approaches still face persistence challenges in vivo and limited infiltration into solid tumor microenvironments. The safety profile suggests these therapies could eventually treat broader patient populations, including those with comorbidities that preclude intensive CAR-T regimens. As genetic engineering techniques mature, CAR-NK therapy may become the preferred cellular immunotherapy platform for many oncological and autoimmune applications.