In contrast, PD-1 expression decreased in both REP TIL CD4+ (18.8%) and CD8+ T cells (14%) compared with the pre-REP TILs (28% and 21.4%) and tumors (41.6% and 54%), indicating that T cells residing in the tumor encompassed the greatest amount of exhaustion (Fig. 1D). Here, PDCD1 is linked to neoplasm.