Study Overview: This study looks at how a drug called duvelisib affects T cells in people with a type of cancer called diffuse large B-cell lymphoma that has either come back or not responded to treatment. T cells are important parts of our immune system. Duvelisib is a pill that can change T cells to make them work better. Researchers want to see how this helps when making a special treatment called CAR-T cells, which are T cells modified to fight cancer.

Process: Participants will take duvelisib twice a day for 2 weeks. This is followed by a treatment with CAR-T cells, and then they will be monitored for 100 days.

• Participation involves taking medicine for 2 weeks and having a follow-up after 100 days.
• The study checks how effective duvelisib and CAR-T cell treatment are together.
• Participants should be aware of potential side effects and will need to follow specific medical instructions.