A Study to Evaluate the Effectiveness and Safety of Polatuzumab in Real World Clinical Practice Among Adult Chinese Participants With Diffuse Large B-Cell Lymphoma

Inclusion Criteria: * Be diagnosed as DLBCL * Cohort 1: diagnosed as unfit/frail DLBCL. The unfit/frail is defined as aged 80 years or older, or younger than 80 years but with comorbidity and not tolerant to the standardized dose of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy according to investigator's judgment * Cohort 2: diagnosis as DLBCL but could not be classified into unfit/frail * Cohort 3: relapse or refractory to previous treatment Exclusion Criteria: * Participant who currently participates in or with plan to participate in any interventional clinical trial * Any other reason that, in the investigator's opinion, makes the participant unsuitable to participate in this study.