A prospective observational cohort study of patients undergoing CPI therapy in which translational research is the fundamental aspect of the study.

The study aims to enroll and obtain samples of investigational interest from 200 patients over a 36-month recruitment period. Blood and/ or stool samples will be taken at baseline, in context of irAE development / during CPI treatment and during follow-up. Skin samples may also be taken upon development of organspeciifc irAEs.

Further assessments at baseline or during the course of or following treatment will be conducted in accordance with standard institutional practice and will be clinically driven. Clinical data, samples and results from archival, current or prospective diagnostic or therapeutic procedures will be used for research purposes within EXACT.

IrAE clinical monitoring will be conducted in accordance with standard institutional practice and will be clinically driven.

Inclusion Criteria:

• Written informed consent
• Age 18 years or older
• Confirmed diagnosis of any form of solid malignancy with a clinical indication and appropriate treatment plan to commence immune checkpoint inhibitor therapy

Exclusion Criteria:

• Medical or psychological condition that would preclude informed consent
• Planned participation in a drug trial receiving investigational agents
• Subjects who have previously commenced immune checkpoint inhibitor therapy prior to study entry.
• Subjects unable to comply with the study or sample schedule.

The study aims to enroll and obtain samples of investigational interest from 200 patients with a confirmed diagnosis of any form of solid malignancy with a clinical indication and appropriate treatment plan to commence immune checkpoint inhibitor therapy.