Additional immunotherapeutic agents, including drugs that target either checkpoint molecules, such as TIM-3 [261], LAG-3 [176], or VISTA [262] or immune-metabolic checkpoints such as adenosine (A2A-receptor antagonist, CD73 or CD39 inhibitors) and IDO, yielded promising results in preclinical tumor models [263,264,265] and are currently evaluated in conjunction with anti-PD-1/L1 treatments [254]. Here, IDO1 is linked to neoplasm.