PLAC1 and head and neck squamous cell carcinoma: Moreover, through ST analysis, multiplex immunofluorescence (mIF) staining, and experimental validation, we revealed that Plac1+ tumor cells generate a Treg‐related immunosuppressive TME, which in turn activates tumorigenic signaling in Plac1+ tumor cells; this then forms a reciprocal loop for HNSCC progression.