CD4 and neoplasm: As a result, PDI(Br)6 NPs+laser treated tumor showed an increase in recruitment of CD3+CD4+ T cells into the tumor by 29.9%, which was 1.88, 1.68, and 1.46‐fold higher than the PBS (15.9%), PBS + laser (17.7%), and PDI(Br)6 NPs (20.4%) groups (Figure 6i–k).