CTLA4 and cancer: This novel approach towards cancer therapy has been well studied using anti-PD-1/PD-L1 and anti-CTLA-4 inhibitors with durable response rates in patients with various cancer types, and research has extended towards blockade of other tumor-associated immune checkpoint molecules, such as CD200, involved in modulating the immune response, including the combination of immune checkpoint blockade therapies with other treatments [4,5,6,7].