PDCD1 and hepatocellular carcinoma: When comparing TIL populations between naïve and HCC tumor bearing mice, the presence of developing HCC tumor in the liver induced expansion of a CD8+ T cell population with markers of terminal effector cells, as defined by high Tim-3 (CD366) and PD-1 expression (Fig. 3A), at day 38 post hydro-dynamic injection (Fig. 3C–D).