CD28 and neoplasm: More importantly, engineered synthetic ‘switch’ receptors-T cells that fuse inhibitory receptor structural domains to activation structural domains, including TIGIT-CD28 [215], CD200R-CD28 [216], TIM-3-CD28 [217], PD-1-CD28 [218], have shown superior anti-tumor capabilities in preclinical models or clinical trials, providing a realistic basis for remodeling solid tumor ACT.