Lastly, Schenk et al. published the results of a prospective, multi-center phase I/II trial, in which eight evaluable KTR with multiple advanced skin cancers received PD-1 inhibitor monotherapy with nivolumab, and subsequently had the option of transitioning to dual ICI blockade with PD-1 and CTLA-4 inhibition with ipilimumab and nivolumab (6/8) for progressive disease [29]. Here, CTLA4 is linked to skin cancer.