Therefore, it is possible that the IFN‐γ‐STAT1 axis induced by CD4+ or CD8+ T cells, or macrophage‐producing IL‐6‐STAT3 axis, might serve as the primary mechanism of PD‐L1 expression by PDA cells and Tregs infiltration into the TME 29, 30. Here, IL6 is linked to Patent ductus arteriosus.