PDCD1 and lymphoma: Along the same line, after addition of high-dose Vit-C (1.5 M) with anti-PD1 (200 μg) antibodies in a lymphoma mouse model, high-dose Vit-C therapy improved tumor immune recognition, and resulted in enhanced macrophage and cytotoxic T cell infiltration, which is not seen with anti-PD1 treatment alone.