Immune checkpoint blockade therapies such as PD-1 antibodies such as Pembrolizumab and Nivolumab, anti-PD-L1 antibodies such as Avelumab, Durvalumab, and Atezolizumab, and humanized CTLA-4 antibodies such as Tremelimumab and Ipilimumab have exhibited powerful and lasting anti-tumor action. Here, PDCD1 is linked to neoplasm.