PDCD1 and cancer: The combination with PD-1 blockade demonstrated promising results, as immunotherapy with antibody-mediated blockade of LAG-3 alone shows limited efficacy in models of chronic viral infection and cancer, and the dual blockade of PD-1/LAG-3 synergistically reduced viral load by countering CD8+ T-cell exhaustion in chronic lymphocytic choriomeningitis virus infection, thus improving antiviral CD8+ T-cell responses [45].