In a phase 3 clinical trial (CheckMate 143), 369 patients diagnosed with GBM who experienced a 1st relapse following standard radiotherapy and temozolomide (TMZ) treatment were randomly allocated in a 1:1 ratio to receive either Nivolumab, an anti-PD-1 therapy, or Bevacizumab. Here, PDCD1 is linked to glioblastoma.