Abstract
In the landscape of tumor immunotherapy, T cell-mediated immune responses have consistently captured the attention, while the contributions of B cells have been neglected. Nevertheless, growing evidence underscores the pivotal role of tumor-infiltrating B cells and plasma cells, collectively termed tumor-infiltrating B lymphocytes (TIL-B), in cancer treatment. These cells not only contribute significantly to therapeutic outcomes and prognostication in the realms of standard treatment and immune checkpoint inhibition but also open avenues for novel immunotherapeutic strategies. Interestingly, the heterogeneity within TIL-B populations, marked by diverse phenotypic subgroups, provides them with the capacity to exert both antitumor and protumor influences. Therefore, a comprehensive understanding of TIL-B interactions with tumors would be helpful for harnessing TIL-B as targets in tumor immunotherapy. Here, we survey the current state of TIL-B research with the aim of elucidating their role in tumor immunotherapy and offering insights for the development of TIL-B-based therapeutic approaches.