Published in September 2020, this study showed that "THC-treated mice did not exhibit marked inflammation compared to the group that did not receive THC treatment."
Researchers at University of South Carolina School of Medicine induced colon cancer in mice to investigate the effects of THC. The mice that were given THC treatment did not develop colitis-induced colonic cancer and didn't show an increase in spleen size. They also lost less weight compared to the control group.
A summary article from Terpenes & Testing Magazine is here.