PDCD1 and cancer: Our findings suggest that GSK-3 inhibitors could be used to substitute or complement anti-PD-1 or PD-L1 therapy presently in use in infection and cancer (Barber et al., 2006, Day et al., 2006, Freeman et al., 2006, Grakoui et al., 2006, Ha et al., 2008, Wolchok et al., 2013) or in combination with CTLA-4 blockade (Topalian et al., 2015, Wolchok et al., 2013).