Study of Pomalidomide Combination with Rituximab and Anti-PD-1 Antibody （PPR） in Third or Later Line Therapy of DLBCL

This study is testing a three-drug combination — pomalidomide, rituximab, and an anti-PD-1 immunotherapy drug — as a third or later line treatment for diffuse large B-cell lymphoma (DLBCL), an aggressive blood cancer, in patients whose cancer came back or did not respond to at least two prior treatments. **You may be eligible if...** - You are between 18 and 80 years old - You have been diagnosed with DLBCL confirmed by biopsy with measurable disease - Your cancer did not achieve a complete response or came back after at least two prior lines of treatment - Your overall health level (ECOG score) is 0–2 - You agree to use contraception during and for six months after the study **You may NOT be eligible if...** - You have active hepatitis or other serious infections - You are pregnant or breastfeeding - Your organ function does not meet required levels Talk to your doctor to see if this trial is right for you.