• Patients voluntarily participate in this study, sign informed consent and comply with the study trial protocol

• Age ≥ 18 years

• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2

• FL (grade 1 - 3a), MZL, WM, HCL-v with histological documentation of CD20 positivity

• Systemic therapy as assessed by the investigator based on tumor size and/or GELF criteria

• Histological confirmation of MZL. For splenic marginal zone lymphoma (SMZL) for which splenic histological specimens cannot be obtained, it is required to meet the minimum diagnostic criteria for SMZL and rule out any other type of small B-cell lymphoma, that is, it is required to confirm the diagnosis of MZL. If the patient had gastric extranodal MZL with symptoms: H. pylori-negative primary lesion or re-lesion after local therapy (i.e., surgery or radiation therapy), the investigator judged whether treatment was required, and if H. pylori-positive, stable disease, progression, or recurrence after antibiotic treatment, the investigator judged whether treatment was required

• Waldenström macroglobulinemia,lymphoplasmacytic lymphoma,WM/LPL(WM/LPL): meets the diagnostic criteria for WM/LPL and is indicated for treatment (meets at least one of the following conditions): symptomatic hyperviscosity; symptomatic peripheral neuropathy; amyloidosis; cold agglutinin disease; cryoglobulinemia; disease-related cytopenias (Hb \< 100 g/L, PLT \< 100 × 109/L); giant lymph nodes; those with systemic symptoms: persistent for two weeks/recurrent fever (above 38℃) and not caused by infection, or night sweats and/or weight loss \> 10% within 6 months; rapid disease progression, such as lymph node enlargement of more than 50% within 2 months, and/or absolute doubling time of peripheral blood lymphocytes \< 6 months, and/or rapid decrease in hemoglobin or platelets due to non-autoimmune causes

• HCL-v: Meet the WHO diagnostic criteria (4th Edition, 2016), and treatment is indicated

• At least one two-dimensional measurable lymph node lesion (maximum diameter \> 1.5 cm by CT scan or MRI), or at least one two-dimensional measurable extranodal lesion (maximum diameter \> 1.0 cm by CT scan or MRI)

⁃ Life expectancy ≥ 3 months

⁃ Adequate blood function (except for abnormalities considered by the investigator to be due to the underlying disease of lymphoma), defined as follows: hemoglobin ≥ 7 g/dL absolute neutrophil count ≥ 1.0 × 10\^9/L platelet count ≥ 50 × 10\^9/L

⁃ Normal laboratory values: creatinine clearance ≥ 30 mL/min AST or ALT ≤ 2.5 x upper limit of normal (ULN) Serum bilirubin ≤ 2 x ULN (≤ 3 x ULN for patients with Gilbert's syndrome) measured or estimated according to institutional standard methods

⁃ For men who are not surgically sterile: Agree to use barrier contraception during treatment and for at least 3 months after the last dose of otuzumab or bendamustine or as required by guidelines established by the institution, whichever is longer. In addition, male patients must agree to have their partner use an alternative method of contraception (e.g., oral contraceptive, intrauterine device, barrier method, or spermicide)

⁃ For women who are not surgically sterilized: agree to use two appropriate methods of contraception, such as oral contraceptives, intrauterine devices, or barrier methods, with spermicide for at least 28 days before starting study drug, during treatment, and for at least 12 months after the last dose of otuzumab or bendamustine, or for the time required by the guidelines established by the study institution (whichever is longer)