This study is aimed at understanding the impact of gut microbiota on efficacy of cancer therapies, in particular checkpoint inhibitors, and using the resulting information to design microbial immunotherapies. Although animal models are of use to determine the influences of gut and other microbiota on cancer treatment modalities, they are limited due to differences between mouse and human physiology and immunology, as well as the inherent differences in gut microbial populations between the two mammalian organisms. Therefore, samples obtained as donations from human subjects undergoing cancer treatment are of great value for the identification and determination of bacteria and their metabolic processes that are involved in the successful cure and remission of cancer by checkpoint inhibitor therapies. The objective of this study is to collect 3 samples each of blood, urine, and stool in subjects with cancer. This is a non-interventional, 2 site study in 100 people who are undergoing any type of cancer immunotherapy. Subjects who meet the entry criteria will provide 5 samples each of blood, urine, and stool over a 12-month period.