In the Research Article “An oral heme oxygenase inhibitor targets immunosuppressive perivascular macrophages in preclinical models of cancer” by M. Bahri et al., the dose of gemcitabine was incorrectly reported as 6.6 mg/kg in the captions of Figs. 1, 3, 5, and 6. All instances of the incorrect dose have been corrected to read 332 mg/kg. The incorrect value reflects the absolute amount of drug typically administered to a 20-g mouse rather than the correct allometrically scaled dose used in the study that was tailored to body weight. The conclusions and other data in the paper are not affected.