A real-world retrospective cohort study of 155 patients with brain metastases found no association between immunotherapy timing relative to stereotactic radiosurgery and overall survival, intracranial control, or toxicity. The analysis suggests timing adjustments may not produce measurable outcome differences in routine practice. For clinicians and trial designers, the finding pushes against simplistic sequencing assumptions and highlights the importance of prospective designs with standardized timing definitions. Operationally, it supports focusing on regimen selection and patient-specific radiosurgical planning rather than relying on generalized “timing windows” for immunotherapy around SRS.