Zanubrutinib Plus GCVP (Obinutuzumab, Cyclophosphamide, Vindesine, Prednisolone) in Previously Untreated Follicular Lymphoma Previously untreated patients with follicular lymphoma are treated with the ZGCVP regimen (zanubrutinib, obinutuzumab, cyclophosphamide, vindesine, prednisolone) for 6 cycles. This is a prospective, single-arm, multi-center, phase II clinical study aiming at evaluating the efficacy and safety of zanubrutinib with GCVP (obinutuzumab, cyclophosphamide, vindesine, prednisolone) in untreated follicular lymphoma (FL). It includes screening (14 days before the first dose), treatment, and follow-up phases. Screening: Recruitment subjects are grade 1-3a, stage III/IV or extensive stage II (unsuitable for radiotherapy) FL patients, with measurable lesions (short axis ≥1.5cm