Improving the immune microenvironment has become a major priority as humans face a variety of unexpected virus-es and bacteria.Hyperbaric oxygen therapy(HBOT)has been proven to be a safe and effective adjunctive therapy in recent years and is widely used in clinical practice.With the advancement of science and technology and in-depth research on hyperbaric oxygen,more and more studies have shown that hyperbaric oxygen has a positive effect on improving the human immune microenvironment.This arti-cle reviews the possible mechanisms of hyperbaric oxygen on the immune microenvironment and its research related to various diseases.