CD4 and neoplasm: Taken together, immune activation in immunotherapy-responding tumors is reflected in characteristic changes in tumor immune contexture, increased expression of antigen-presenting molecules and immune checkpoints on both tumor and myeloid cells, and increased T-cell reactivity in both CD8 and CD4 compartments, with the highest magnitude of changes observed following combined (anti-PD1 plus anti-CTLA4) immunotherapy.