Prasad Adusumilli, MD, FACS, Memorial Sloan Kettering Cancer Center, New York, NY, comments on the importance of co-stimulatory molecules for immunotherapies, which have come to play an important role in treating solid tumors. Co-stimulatory molecules are required by immune cells such as T-cells and hence T-cell therapies to be activated . Whilst antigen-presenting cells can provide co-stimulation, Prof. Adusumilli further describes strategies to provide co-stimulation in T-cell receptor (TCR) therapies and chimeric antigen receptor (CAR) therapies. This interview took place at the 2022 Targeted Therapies of Lung Cancer Meeting (TTLC 2022).