Chitosan has a rich history of being investigated for applications in various fields such as food and nutrition, material science, medical science, immunological stimulation, anti-microbiological as well as other biological effects. Unfortunately, the effects are unlikely to be of medical importance. However, The recent researches have reported the potential and promising significance of their derivatives and formulation towards immunotherapy adjuvant: immunomodulating activity and antitumor immunity effects. In this overview, we have summarized the research and development of the immune-regulating and enhancing properties of chitosan, chitosan derivatives and formulations including antitumor immune action and chitosan derivatives in immune cells in vivo and in vitro by years. To our knowledge, chitosan and its derivatives could be a promising immunotherapy adjuvant for medical and pharmaceutical applications.