Unfortunately, however, according to the TIDE results, the probability of immune escape was not significantly different between the two risk groups, which may explain why single-agent programmed death 1 ligand (PD-L1) or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors is ineffective for PC [69–71]. This evidence concerns the gene CTLA4 and pachyonychia congenita.