The fundamental mechanisms underlying this synergy were revealed as follows: (i) Glioblastoma requires substantial CD8+ NK cell infiltration; (ii) DC vaccination makes brain tumors permissive to T-cell infiltration; and (iii) subsequent PD-1 blockade neutralizes the suppressive checkpoint “shield” that would render T-cells dysfunctional (67). The gene discussed is PDCD1; the disease is glioblastoma.