This trial is a multicentric, prospective cohort study of 150 patients aiming to model evolution of toxicity over time in patients with solid tumor and starting first cycle of Immune Checkpoint Inhibitor (ICI) treatment.

The study will be conducted on a population of patients treated with ICI in the context of routine care. The follow-up during the treatment period and the clinical, biological and radiological assessments will be performed according to the standard of each centre.

The study data (immune-related adverse events) will be collected during each administration of the treatment.

A questionnaire will be completed by the patient before the treatment administrations.

Patients will be followed until disease progression or up to 12 months of treatment.

Inclusion Criteria:

1. Age > or = 18 years old
2. Patient with a solid tumor whatever the organ
3. Patient receiving an Immune Checkpoint Inhibitor treatment
4. Patient starting first cycle of Immune Checkpoint Inhibitor treatment whatever the treatment line
5. Patient affiliated to the french social security system
6. Patient must provide written informed consent prior to inclusion in the study and any study-specific procedure

Exclusion Criteria:

1. Patient who must receive a treatment other than Immune Checkpoint Inhibitor
2. Patient with contraindication to the use of a checkpoint inhibitor (e.g., auto immune disorders requiring an immunosuppressive therapy)
3. Pregnant or breastfeeding women
4. Any psychological, familial, geographical or sociological condition potentially preventing the medical follow-up and/or study procedures
5. Patient protected by law