PDCD1 and neoplasm: Further, anti-PD-1 treatment abrogated PD-1 expression on xenograft infiltrating DNT cells as shown by the lack of staining using anti-PD1 clone EH12.2H7 that recognizes a Nivolumab shared epitope of PD-1 [33, 34] (Fig. 5a), suggesting that the Nivolumab treatment effectively blocked the PD-1 epitope on tumor infiltrating DNT cells.