A patient-level synthesis of 40 published cases shows nivolumab-induced hypophysitis primarily damages the pituitary’s cortisol-regulating axis, typically responds to corticosteroids, and rarely recurs after restarting therapy (ID: 8b6ef3d3955199e6). The analysis strengthens the clinical profile of this immune-related adverse event at a granularity that case reports alone can’t provide. For oncology teams, the findings help sharpen risk expectations and management planning—particularly around hormone axis targeting and steroid responsiveness. The low recurrence signal also informs re-challenge discussions when cancer control depends on continued checkpoint inhibition. The work is positioned as a practical reference for clinicians managing endocrine immune toxicity rather than a mechanistic study, but it still matters for how checkpoint regimens are supported during treatment courses.