Additional Study Information: The purpose of this study is to find out the safety, effectiveness, and blood levels of various doses of the study drug in participants with T-cell lymphoma that has not improved or has gotten worse. ONO-4685 is an experimental drug which is not approved by Health Authorities including the United States Food and Drug Administration (FDA). The study drug is a protein made in laboratory called an antibody. Antibodies are made naturally in our body and are a key part of our immune system. The study drug antibody targets 2 specific proteins: a protein called PD-1 on cancer cells and protein called CD3 on immune cells. The goal of the study drug is to improve your immune system's ability to fight the cancer cells.