CD4 and neoplasm: More specifically, during the recovery phase of PDT treatment, the levels of M2‐type macrophages significantly increase, which may lead to tumor recurrence.[50] In the current study, analysis of the immune microenvironments of the primary and distant tumors in MFC‐615 mice revealed an increase in the CD3+, CD4+, and CD8+ T cell numbers and proportions, along with reduced Treg levels, and evidence of M1 macrophage polarization.