The development of single-cell lineage tracing technology and its application in immunotherapy.

Immunotherapy stands as one of the most promising approaches in cancer treatment, with engineered T cell therapies, particularly chimeric antigen receptor T cell (CAR-T), leading the charge. However, relapse in some patients post-treatment suggests that research in this field remains incomplete. Tumor heterogeneity and the complexities of the immune microenvironment hinder a comprehensive understanding of the changes engineered T cells undergo once introduced into the human body. Single-cell lineage tracing (SCLT) technology facilitates the investigation of cellular development by monitoring the fate and differentiation of individual cells and their descendants within an organism. Employing methodologies such as CRISPR-based labeling and mitochondrial DNA tracking, SCLT allows for dynamic analysis of T cell clonal evolution, exhaustion mechanisms, and memory cell generation. This approach offers single-cell resolution data that contribute to resolving pertinent clinical challenges. This article provides a comprehensive review of recent developments and characteristics of the SCLT multi-omics approach. It elucidates the manner in which SCLT addresses the conventional constraints associated with spatiotemporal resolution and introduces a novel methodology for generating DNA barcodes to monitor CAR-T cells via CRISPR technology. These contributions offer valuable perspectives for the enhancement of cell therapy strategies.