OT-1 splenocytes with CD8+ T cells specific to ovalbumin peptide of amino acids 257 to 264 (SIINFEKL) were primed with the SIINFEKL peptide to simulate the clinical scenario in which T cells infiltrate tumors and recognize cancer cells; however, they become dysfunctional by PD-1 receptor ligation of PD-L1 expressed by cancer cells. Here, CD8A is linked to cancer.