1. CTLA-4 and PD-1 are both immune checkpoint proteins that regulate T cell activation by binding to their respective ligands.
2. Anti-CTLA-4 and anti-PD-1 targeted drugs have been developed to treat cancer, but there are still limitations and further research is needed.
3. Humanized mouse models of immune checkpoints, such as CTLA-4-HU and PD-1-HU, can be used to study drugs targeting human immune checkpoints and predict drug efficacy and possible side effects before clinical trials.