Innate Immune Cells and Their Contribution to T-Cell-Based Immunotherapy

In recent years, immunotherapy has become the most promising therapy for a variety of cancer types. The development of immune checkpoint blockade (ICB) therapies, the adoptive transfer of tumor-specific T cells (adoptive cell therapy (ACT)) or the generation of T cells engineered with chimeric antigen receptors (CAR) have been successfully applied to elicit durable immunological responses in cancer patients. However, not all the patients respond to these therapies, leaving a consistent gap of therapeutic improvement that still needs to be filled. The innate immune components of the tumor microenvironment play a pivotal role in the activation and modulation of the adaptive immune response against the tumor. Indeed, several efforts are made to develop strategies aimed to harness innate immune cells in the context of cancer immunotherapy. In this review, we describe the contribution of innate immune cells in T-cell-based cancer immunotherapy and the therapeutic approaches implemented to broaden the efficacy of these therapies in cancer patients.