Israel’s Biomica (see here previously) has given 12 cancer patients, who had poor responses to immunotherapy, pills containing bacteria missing from their gut microbiome. In 2020, doctors at Sheba hospital used fecal bacteria to shrink the tumors of three cancer patients.

https://www.timesofisrael.com/israeli-company-to-test-if-fecal-bacteria-pills-boost-cancer-immunotherapy/