(A) NIR-PIT regimen. Bioluminescence and fluorescence images were obtained at each time point as indicated. (B) Light exposure. NIR light was administered to the caudal right-side tumor only in mice bearing four tumors. All other tumors were shielded from NIR light. (C) In vivo IR700 fluorescence real-time imaging of tumor-bearing mice in response to NIR-PIT treatment to the caudal right-side tumor only. (D) In vivo BLI of tumor bearing mice in response to NIR-PIT treatment of the caudal right-side tumor only. (E) Quantification of luciferase activity in all tumors from controls and mice treated with combination NIR-PIT and PD-1 mAb. Only the caudal right-side tumor received NIR-PIT treatment (n = 10, **p < 0.01, Tukey’s test with ANOVA). (F) Resected tumors (day 10) were stained with H&E and assessed for necrosis and leukocyte infiltration. White scale bars = 100 μm. Black scale bars = 20 μm. (G) Growth curves from controls and treated and untreated tumors from mice receiving combination NIR-PIT and PD-1 mAb. (H) Kaplan-Meier survival analysis (n = 10, **p < 0.01, Tukey’s test with ANOVA for growth curves; **p < 0.01, Log-rank test for survival).