PDCD1 and glioblastoma: Clinical trials evaluating combination treatment strategies with checkpoint inhibitors are likewise underway, including a Phase 2 trial studying the PD-1 inhibitor retifanlimab in combination with bevacizumab and hypofractionated radiation for recurrent GBM (NCT06160206), and a Phase 2 trial combining pembrolizumab with a long-acting recombinant interleukin-7 (NT-I7) for recurrent GBM (NCT05465954).