CTLA4 and cancer: 7HP349 monotherapy had modest effects on anti–programmed death 1–resistant (anti–PD-1–resistant) tumors, whereas combinatorial treatment with anti–cytotoxic T lymphocyte–associated protein 4 (anti–CTLA-4) increased CD8+ Teff intratumoral sequestration and synergized in cooperation with neutrophils in inducing cancer regression.