Several studies suggested that the immune checkpoints PD-1, CTLA-4, and T-cell immunoglobulin and mucin-domain containing-3 (TIM-3; Liu et al., 2017; Naoum et al., 2018; El Dika et al., 2019) are crucial indicators sustaining the pro-tumor immune microenvironment. The gene discussed is CTLA4; the disease is neoplasm.