BCL6 and B-cell non-Hodgkin lymphoma: Patients 18 years or older with R/R large B‐cell lymphoma (transformed or de novo DLBCL, primary mediastinal B cell lymphoma and high‐grade B‐cell lymphoma with MYC rearrangement plus rearrangement of Bcl2, Bcl6 or both), FL grade 3B or relapsed MCL