- Participants should be excluded if they have had prior treatment with an anti-PD-1, anti-programmed cell death ligand 1 (PD-L1), anti-programmed cell death ligand 2 (PD-L2), anti-CTLA-4 antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways; prior immune modulating therapy including vaccines may be eligible; prior immune events must be evaluated and the risk for new events which may represent continued sub clinical disease or a new process at previously damaged site or immune potentiation (e.g. ipilimumab followed by IL2 causing bowel perforation, ipilimumab followed by indoleamine 2,3-dioxygenase [IDO] inhibitor resulting in clinical hypophysitis); please keep in mind that inflammatory events may occur weeks to months following the last dose of ipilimumab and possibly nivolumab; assessment of potential effects of prior therapy should include: