This is a pilot, randomized, two arm neoadjuvant vaccine study in human leukocyte antigen-A2 positive (HLA-A2+) adults with World Health Organization (WHO) grade II glioma, for which surgical resection of the tumor is clinically indicated. Co-primary objectives are to determine: 1) the safety of the novel combination of subcutaneously administered IMA950 peptides and poly-ICLC (Hiltonol) and i.v. administered CDX-1127 (Varlilumab) in the neoadjuvant approach; and 2) whether addition of i.v. CDX-1127 (Varlilumab) increases the response rate and magnitude of CD4+ and CD8+ T-cell responses against the IMA950 peptides in post-vaccine peripheral blood mononuclear cell (PBMC) samples obtained from participating patients.