In contrast, for Hepa1-6, where CD8+-CTL seems to play less role in anti-PD-1 response as described above (Table 1 Experiment 2), the TIL-CD8+ depletion together with anti-PD-1 treatment did not cause M2-macrophage enrichment in the tumors (Fig. 3C), but instead resulted in an increase in the levels of CD4+ T cells (116%) and Treg (75%) potentially suggesting an equilibrium between TIL-Treg and TIL-CD4+ Teff in Hepa1-6 model, correlating to (rendering) the observed tumor growth inhibition by anti-PD-1 treatment through CD4+-Teff and Treg. Here, PDCD1 is linked to neoplasm.