We also did not examine fungi, including yeasts, which have roles in human cancers.14,15 For example, Saccharomyces paradoxus was associated with an increased response to anti-PD-1 immunotherapy in melanoma, while increased levels of Malassezia restricta and Candida albicans were linked with an increased risk of progression and worse response to anti-PD-1 treatment.15 This evidence concerns the gene PDCD1 and cancer.