However, it is important to note that these differences may be overestimated and that both anti-PD-1 and anti-PD-L1 agents have a similar toxicity profile (7).It has been reported that PD-1 and PD-L1 have high levels of expression in heart tissue, and PD-1 and CTLA-4 can cause Myocarditis (8, 9). The gene discussed is CTLA4; the disease is myocarditis.