PDCD1 and melanoma: investigated combined vidutolimod (TLR9 agonist) and nivolumab (PD‐1 inhibitor) therapy in high‐risk resectable melanoma, demonstrating that major pathological response (MPR) is associated with tumor necrosis, melanophagocytosis, and an increase in CD8+ TILs and plasmacytoid dendritic cells (pDCs) in the TME.[197] These coordinated immune cell alterations reflect pro‐inflammatory reprogramming of the TME following effective ICIs.