A phase 1 trial is investigating the use of anti-LAG-3 with or without anti-PD-1 in recurrent glioblastoma. The effectiveness of checkpoint inhibitors, including anti-PD-1, in treating glioblastoma is being explored, with some research suggesting that current approaches may not be sufficient. The interaction between tumor cells and immune cells, including regulatory T cells and neutrophils, may play a role in the response to immunotherapy for glioblastoma.