Background: Primary Liver Cancer is the second most common cause of cancer-related death worldwide. It is the cancer with the fastest rising incidence and mortality in the United States. Researchers want to learn more about liver cancer to help them design better treatments.

Objective: To better understand liver cancer.

Eligibility: People ages 18 and older who have liver cancer and had or are planning to have immune therapy

Design: Participants will be screened with a review of their medical records. They will be asked about their medical history and test results. Participants will come to the NIH Clinical Center. During this visit, their medical records, test results, imaging studies, and tissue samples (if available) will be gathered. Participants will learn the results of a test to see if they have any mutations known to be connected to cancer. They will learn if there are treatment options for them. Participants will give blood, urine, and stool samples or rectal swabs. Participants will not have follow-up visits just for this study. If they join another NIH research study and have visits for this other study, their medical records; test results; and blood, urine, and stool samples may be collected. This will occur about every 3 months. If they have a biopsy or surgery on another study or as part of treatment and there is leftover tissue, researchers would like to collect some of that tissue. Participants will be contacted every 6 months by phone or e-mail. They will be asked about their health. They will provide any medical records, test results, and imaging studies. Participants will be followed on this study for life.