PDCD1 and neoplasm: Next, we determined the co-localization of PD-1/PD-L1: 80.4% (37 of 46) of the tumor samples had co-localization in >1% of the cells, 4.3% (2 of46) co-localized in > 20% of the cells, and none co-localized in > 50% of the cells.