CTLA4 and cancer: In recent years, immunotherapy has rapidly developed and benefits some cancer patients by affecting immune checkpoints, including the cytotoxic T lymphocyte associated protein 4 (CTLA-4) or the programmed cell death 1 (PD-1) signaling pathway [2, 3], which is a promising approach to activate antitumor immunity and can improve T cell function and reduce tumor burden by strengthening cytotoxic CD8+ T cell (CTL) infiltration to slow tumor progression and prolong patient survival.