PTX3 and cancer: Our immunohistochemistry results further confirmed that, in the context of cancer, myocardial infarction thrombi exhibited significantly enhanced local infiltration of CD8+ T cells and Treg, as well as upregulation of PTX3, whereas CXCL8 and PD‐L1 levels remained largely unchanged, highlighting the complexity and diversity of the cancer–myocardial infarction microenvironment.