Study schedule Dose levels of this study are defined by dose of drug as well as number of treatments and required interval from last treatment to surgery. At least 3 subjects in a dose cohort must complete the dose limiting toxicity (DLT) evaluation period before dosing is initiated at the next higher dose level. Only toxicities occurring during the DLT period will be considered as DLTs and utilized to inform dose escalation decisions. The DLT period starts with the first dose of pembrolizumab till 30 days post-surgery.