To further understand mechanism(s) for the superior bioefficacy of skin immunization, we focused on treatment-evoked changes in tumor-infiltrating CD8+ T cells and CD4+ T cells, which have recently attracted attention in the context of effective αPD1-based immunotherapy.15–22 Skin immunization increased tumor-infiltration by CD8+ T cells in both the tumor margin and core (figure 7A, B), consistent with observed IFNγ+CD8+ TIL persistence (figure 6C). This evidence concerns the gene CD4 and neoplasm.