Analysis of hematoxylin and eosin (H&E) stained tumor tissue shortly after DNT treatment revealed that though tumor size remained similar (181.0 ± 53.7 mm3 for DNT cell treated vs 152.2 ± 54.7 mm3 for DNT cell and anti-PD-1 treated), anti-PD-1 significantly increased the proportion of necrotic area detected within tumors from mice receiving combination treatment (64.9 ± 11.7% vs 41.3 ± 14.5%; Fig. 4d), with a similar result observed for i.v. inoculated DNT cells (42.1 ± 10.4% vs 22.4 ± 7.2%; Additional file 2: Figure S5D). Here, PDCD1 is linked to neoplasm.