This study is planned to prospectively observe and verify the efficacy and safety of induction therapy with obinutuzumab in combination with lenalidomide followed by maintenance therapy with obinutuzumab and lenalidomide in patients with R/R FL in a real-world setting in a Chinese population.

Available data have shown that the combination of obinutuzumab and lenalidomide has shown good efficacy and safety in patients with R/R FL, but the efficacy and safety in Chinese patients remain to be verified.

This study is planned to prospectively observe and verify the efficacy and safety of induction therapy with obinutuzumab in combination with lenalidomide followed by maintenance therapy with obinutuzumab and lenalidomide in patients with R/R FL in a real-world setting in a Chinese population.

The main questions it aims to answer are:

• To assess the ORR in the R/R FL patient population treated with the combination of obinutuzumab and lenalidomide
• To assess CRR, PFS, EFS, DOR, OS, and safety in patients with R/R FL treated with the combination of obinutuzumab and lenalidomide

Participants in this study will not and should not result in any intervention to the patient's treatment and visits. All treatments and visits for patients will be at the physician's discretion according to clinical practice

Patients must meet the following criteria for study entry::

• Signed Informed Consent Form
• Age ≥ 18 years at enrollment
• At least one prior line of systemic (Stage III-IV) follicular lymphoma therapy
• Relapsed or refractory to front-line anti-lymphoma therapy; refractory is defined as: tumor shrinkage of less than 50% or disease progression after 4 cycles of standard regimen chemotherapy; response to standard regimen chemotherapy, relapse within 24 months; 2 or more relapses, meeting one of the above criteria as refractory lymphoma.
• Conditional treatment with obinutuzumab in combination with lenalidomide

Exclusion Criteria:

• Patients currently participating or planning to participate in any interventional clinical trial
• Any other reason that, in the opinion of the investigator, makes the patient unsuitable for this study

This study will include the population of patients with relapsed and refractory follicular lymphoma who are planned to receive the combination of obinutuzumab and Lenalidomide in 9 centers (including 8 sub-centers outside of the Institute of Hematology & Blood Diseases Hospital )