This is a retrospective clinical study aimed at observing and evaluating the effectiveness and safety of checkpoint inhibitors in the treatment of patients with solid tumors in actual clinical applications. To explore predictors of efficacy patients with unresectable solid tumors receiving checkpoint inhibitors and develop and further validate predictive models.

The clinical data of patients with unresectable solid tumors were collected retrospectively, who received two or more cycles of checkpoint inhibitor therapy. The progression-free survival (PFS), overall survival (OS) and related adverse reactions of the patients were followed up. To screen prognostic factors, develop predictive models and visualize them as nomograms.

Inclusion Criteria:

• Age ≥ 18 years old and gender is not limited.
• Patients with unresectable solid tumors confirmed by pathology or histology.
• Patients received checkpoint inhibitor therapy for 2 cycles or more.

Exclusion Criteria:

• Have a history of immunodeficiency, or suffer from other acquired or congenital immunodeficiency diseases, or have a history of organ transplantation.
• Pre-existing thyroid dysfunction that cannot be maintained within the normal range even with medical treatment.
• Pregnant or breastfeeding women.
• Those who have a history of psychotropic drug abuse and cannot quit or have mental disorders.
• The investigator judges that other conditions are not suitable for inclusion in the study.

Patients with unresectable solid tumors confirmed by histopathology or cytology, and continuously treated with checkpoint inhibitor based treatment for 2 cycles or more.