CTLA4 and atherosclerosis: According to prior murine-based research, PD-1, PD-L1, and CTLA-4 serve as negative regulators of atherosclerosis, blocking the ability for T lymphocytes to upregulate macrophages within arterial walls; therefore, while treating cancerous lesions in the body, immune checkpoint inhibitors allow promotion of monocytic antigen presentation and T lymphocyte proliferation within atherosclerotic plaque lesions [24,25].