CD8A and neoplasm: These results were consistent with O’Brien SM’s findings, which showed that CD103+CD8+ T cells produced more IFN-γ than their CD103- counterparts despite high expression of coinhibitory receptors.40 Although a hallmark of dysfunctional T cells within the tumour microenvironment is the overexpression of coinhibitory receptors, the actual contribution of these coinhibitory receptors to the dysfunctional state is still controversial.41–43 Multiple studies have revealed that coinhibitory receptors are also induced when T cells are highly activated.