CDKN2A and cancer: The patient was not a candidate for immune checkpoint inhibitors (ICI), based on the PD-L1-negative, microsatellite-stable, and mismatch repair-proficient status of the tumor, along with the loss of the cell-cycle regulatory gene CDKN2A. This tumor suppressor gene, which is commonly altered in many human cancers, has also been shown to be a marker for poor response to ICI (21).