HAVCR2 and neoplasm: Inhibitory checkpoints like programmed cell death protein‐1 (PD‐1), T‐cell immunoglobulin mucin‐domain containing‐3 (TIM‐3), and lymphocyte‐activation gene 3 (LAG‐3), are all present on T‐cells and all bind to ligands that are secreted by tumour cells [22].