PDCD1 and breast cancer: Using obese breast cancer preclinical models, Pingili and colleagues demonstrated that although tumors in obese group advanced rapidly, treatment with anti-PD-1 reshaped the local and peripheral TME to increase cytotoxic CD8+ T cell infiltration and proinflammatory M1 macrophages, and decrease immunosuppressive populations like myeloid-derived suppresor cells (MDSCs) (165).