PDCD1 and intermediate coronary syndrome: Though our results did not support a causal association between PD-1/PD-L1 and acute myocardial infarction, angina pectoris, coronary atherosclerosis, as well as unstable angina pectoris, further investigations are needed to clarify the mutual effect between PD-1/PD-L1 and CHD, as well as predictive models that detect intricate relationships and interactions among genetic variations, environmental influences, and the risk of CHD.