ADORA2A and cancer: We are probably just scratching the surface of the potential of cancer immunotherapy, since there are other interesting immune-checkpoint receptors being tested (T-cell Immunoglobulin and Mucin-domain containing-3 (TIM3), Lymphocyte Activating 3 (Lag3), B- and T-Lymphocyte Attenuator (BTLA), Adenosine A2A Receptor (A2AR), etc.)[24].