Furthermore, we distinguished intermetastatic Th1 CD4+ T cell function, which in PC is predominantly governed by immunosuppressive PD-L1 signaling toward CD8+ cells and accompanied by a loss of B cell–dependent MHC-II signaling, potentially resembling a disturbed antigen-presenting function of MHC-II+ B cells in PC. Here, CD274 is linked to pachyonychia congenita.