This study looks at how cancer patients from different racial backgrounds respond to **immune checkpoint inhibitors (ICIs)**, which are medicines that help the immune system fight cancer. The study aims to understand if there are differences in side effects and treatment success between African American (AA) and European American (EA) patients. Participants will provide blood and saliva samples and answer questions about their health. They may also give optional stool samples. The study will last for at least one year, with some follow-up every year after the first treatment.

• **Length**: Participation lasts at least 1 year with yearly check-ins.
• **Visits**: Requires blood, saliva samples, and answering health questions.
• **Compensation**: Not mentioned; focus is on understanding racial differences.

Eligible participants must be at least 18 years old, identify as AA or EA, have invasive cancer, and be starting ICI treatment. They must speak English or Spanish and give consent. People with melanoma or those who have had certain cancer treatments before cannot join. This research could help improve cancer care for everyone.