B-cell lymphomas are a heterogeneous group of malignancies with a high relapse rate after conventional therapies. T-cell-mediated immunotherapies, notably chimeric antigen receptor (CAR) T-cell therapies and T-cell-engaging bispecific antibodies (BsAbs), have transformed treatment paradigms by harnessing the immune system to target malignant cells. This review analyzes the efficacy and safety profiles of several CD19-targeted CAR T-cell therapies and emerging CD20xCD3 BsAbs across various B-cell lymphoma subtypes. While these therapies have demonstrated high response rates and potential for durable remissions, challenges such as cytokine release syndrome, neurotoxicity, and infections remain significant. Understanding these mechanisms and managing adverse effects are crucial for optimizing clinical outcomes and guiding future research in personalized treatment strategies.