Laser Interstitial Thermotherapy (LITT) Combined With Checkpoint Inhibitor for Recurrent GBM (RGBM)

The purpose of this study is to test the side effects and efficacy of using Laser Interstitial Thermotherapy (LITT) combined with Pembrolizumab. LITT is a minimally invasive surgical technique that uses a laser to heat brain tumors. Pembrolizumab is an investigational (experimental) drug that works by helping participants' immune system work correctly to detect and fight cancer cells. Pembrolizumab is experimental because it is not approved by the Food and Drug Administration (FDA), for this use, though it is approved to treat other cancers.