Study Investigating the Safety and Efficacy of Blinatumomab in Combination With Pembrolizumab in Adults With Relapsed or Refractory Diffuse Large B Cell Lymphoma (DLBCL)

Inclusion Criteria:

* Have histologically confirmed diffuse large B-cell lymphoma that is either:
* Refractory after at least one regimen of systemic chemotherapy and/or targeted therapy, or
* In first or later relapse if have received at least 2 systemic regimens since time of diagnosis, or
* Relapsed post-autologous or allogeneic hematopoietic stem cell transplantation (HSCT) with adequate organ function after proximity to transplantation time exclusions
* Have measurable disease
* Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2
* Life expectancy of ≥ 12 weeks in the opinion of the Investigator
* Biopsy proven DLBCL (biopsy proven at least at primary diagnosis of DLBCL)

Other Inclusion Criteria May Apply

Exclusion Criteria:

* Richter's transformation (DLBCL arising in the setting of prior chronic lymphocytic leukemia) or primary mediastinal B cell lymphoma (PMBCL)
* History or presence of clinically relevant central nervous system pathology such as epilepsy, paresis, aphasia, stroke, severe brain injury, dementia, Parkinson's disease, cerebellar disease, organic brain syndrome, or psychosis.
* Has a diagnosis of immunodeficiency or has received systemic steroid therapy (in excess of 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of protocol specified therapy.
* Has undergone prior allogeneic HSCT:
* within the last 5 years OR
* greater than 5 years ago but has active graft versus host disease (GvHD) requiring systemic treatment.
* Has received autologous HSCT within 6 weeks prior to start of treatment.

Other Exclusion Criteria May Apply.