Participants will undergo screening tests to determine if they are eligible to participate. This will involve a complete history and physical examination, vital signs, blood tests including complete blood count (CBC), and serum chemistry (CMP).~Participants will receive one cycle of Temozolomide and Pembrolizumab prior to removing recurrent tumor, followed by three weekly cycles of treatment until progression.
The primary purpose of this study is to test the safety of Pembrolizumab and Temozolomide in treating recurrent glioblastoma and to characterize the effect of this treatment on the participants tumor and immune system..