Turkey Tail is a wild harvested mushroom that is great for all things immunity. How it works is it helps rebalance the gut biome so that nor nutrients can be absorbed. This mushroom has  polysaccharide-K (PSK) and polysaccharide peptides (PSP),which help stimulate and regulate the immune system.
 
In japan Turkey tail has been used along side cancer treatments as a way to boost the immunity, it has been known to boost the effectiveness of a few different cancer treatments such as radiology and chemotherapy. For years in Chinese medicine it has been used to help treat  pulmonary disease. 
 
For more information please feel free to check out https://www.cancer.gov/about-cancer/treatment/cam/hp/mushrooms-pdq