This is a randomized, phase II study for patients with Relapsed/Refractory Large B-Cell Lymphoma. The purpose of this study is to determine how long people with Large B-Cell Lymphoma can live without their disease getting worse when treated with two different combinations of cancer drugs. One group will get tafasitamab + lenalidomide + tazemetostat, and the other group will get tafasitamab + lenalidomide + zanubrutinib. The researchers want to see which combination works better. They also want to figure out the best and safest dose of each drug combination to use in future studies. Tafasitamab is a lab-made antibody that helps the immune system find and attack cancer cells. Lenalidomide is a drug that boosts the immune system and helps fight cancer. Tazemetostat is a drug that blocks a protein (EZH2) that helps cancer cells grow. Zanubrutinib is a drug that blocks another protein (BTK) involved in cancer cell survival. The treatment period may last approximately 1 year and the follow up period may last up to 3 years.