CD28 and neoplasm: Notably, we found higher levels of PD-1 and/or PD-L1 especially on peripheral CD8 TEMRA lacking costimulatory receptors CD27 and CD28 in responders than those in nonresponders, indicating these cells are potentially susceptible to reinvigoration by combined anti-anti-1/PD-L1 ICI treatment as these cells likely retain their proliferative capacity and the ability to infiltrate to the tumor upon treatment (48, 49).