Ischemic optic neuropathy (ION) occurs due to insufficient blood supply to the optic nerve, with anterior ischemic optic neuropathy (AION) commonly associated with giant cell arteritis (GCA). Immune checkpoint inhibitors (ICIs), used in cancer therapy, have been linked to neuro-ophthalmic immune-related adverse events (irAEs), though the development of arteritic anterior ischemic optic neuropathy (AAION) due to ICI therapy is exceptionally rare. This case report describes a 77-year-old male with metastatic renal cell carcinoma on ICI therapy who presented with bilateral vision loss and was diagnosed with AAION. MRI findings supported GCA-AAION with orbital involvement, and the patient showed immediate but partial improvement with corticosteroids, despite a nonconfirmatory temporal artery biopsy. This case underscores the need for heightened clinical awareness of ICI-associated ocular complications and highlights the challenges in diagnosing and managing ICI-induced AAION, emphasizing the need for further research into treatment strategies to mitigate irreversible vision loss.