PDL1, and PD-1 inhibitors have also been used to treat the disease and they work by blocking PD1 and PDL1 receptors on the cell surface. They are often used as the first-line treatment for the disease. This paper will explore PD1 and PDL1 cancer immunotherapy. Among the specific areas that will be focused on include PD1 and PDL1 pathway, the role of PD1 and PDL1, and Cancer Immunotherapy.