Mechanisms of immune suppression in peripheral tissues counteract protective immu-nity to prevent immunopathology and are coopted by tumors for immune evasion. Blood and lymphatic vessels contribute to the immune landscape within a tissue by providing selective entry and exit routes, respectively. The work here investigates potential mecha-nisms by which peripheral lymphatic and blood vessel expression of the T cell inhibitory molecule PD-L1, regulate antitumor immunity. Here I test the hypothesis that PD-L1 expression by blood and lymphatic vasculature limits T cell accumulation in skin and tumors.