PDCD1 and diabetes mellitus: This is a 75-year-old male patient with a past medical history of partial small bowel resection, hypertension, diabetes mellitus, hyperlipidemia, and stage 4 metastatic melanoma currently receiving immunotherapy for one month with Keytruda, a programmed cell death protein 1 (PD-1) inhibitor, who presented to the emergency department (ED) of a South Florida hospital with a chief complaint of a syncopal episode.