People with relapsed or refractory diffuse large B-cell lymphoma who cannot have an autologous stem cell transplant usually have polatuzumab vedotin plus rituximab and bendamustine. The clinical evidence is from a small study that did not directly compare tafasitamab plus lenalidomide with any other treatment. The committee considered that the study results were promising because they show that some people's disease responds to tafasitamab plus lenalidomide. Indirect evidence suggests that people who have tafasitamab plus lenalidomide have more time before their disease gets worse than people who have polatuzumab vedotin plus rituximab and bendamustine. It also suggests that they live longer. But there is uncertainty about these results because the survival times for people having polatuzumab vedotin plus rituximab and bendamustine used in the modelling do not reflect the real-world survival times of the treatment in clinical practice, compared with bendamustine and rituximab alone. The methods used for the indirect comparisons are also not clear.