PDCD1 and glioblastoma: Pre−/clinical evidence points towards a promising therapeutic triangle between poly(I:C), vaccination and ICB in GBM: (i) poly-ICLC-adjuvanted vaccination is capable of generating GAA-reactive PD-1+ T cells [68–71]; (ii) poly(I:C) is a strong maturation signal for DC antigen presentation [12]; and (iii) poly(I:C) has preclinically shown to synergize with ICB in GBM, dependent on antigen-presenting DC [30, 59].