TOP-FLOR: This study is evaluating how safe and effective a new drug is when given in combination with targeted therapy, with or without additional immunotherapy, in people with follicular lymphomaTreatment Of Newly-diagnosed Follicular Lymphoma With CELMoD BMS-986369, Rituximab +/- Nivolumab: An Umbrella Bayesian Optimal Phase II Study.

Inclusion

1. Age 18+ years.
2. Histologically proven CD20 positive Follicular non Hodgkin lymphoma (FL) grades 1-3A (i.e. classical follicular lymphoma according to the current World Health Organization classification).3
3. No previous chemotherapy, or other investigational drug for this indication apart from focal radiotherapy.
4. Stage II-IV disease (Ann Arbor criteria).
5. Eastern Collaborative Oncology Group (ECOG) performance status 0 to 1 unless attributable to lymphoma, in which case patients of performance status 2 are also eligible.
6. Deemed to need treatment by treating investigator. Reasons for treatment can include, but are not limited to:

a. Any nodal or extranodal tumour mass >7cm AND/OR multiple extranodal disease sites b. Involvement of at least 3 sites each with diameter >3cm c. Symptomatic splenic enlargement d. Organ involvement/compression e. Ascites or pleural effusion f. Lactate Dehydrogenase (LDH) elevated g. Presence of systemic symptoms h. Disease progression in preceding 3 months i. Evidence of marrow infiltration with marrow compromise. (e.g., Hb, WCC or plt count below lower limit of institutional normal range).

g) Adequate bone marrow function including:

1. Haemoglobin >8.0 g/dL
2. White cell count (WCC) ≥2000/μL
3. Neutrophils >1.5 x 109/L
4. Platelets >75 x 109/L at the time of study entry, unless attributed to bone marrow infiltration by lymphoma.

h) Adequate renal function with serum creatinine ≤1.5 x ULN or creatinine clearance (CrCl) ≥ 60mL/min (using Cockcroft-Gault formula, 24hr urine collection or eGFR).

Female CrCl = (140 - age in years) x weight (kg) x 0.85 72 x serum creatinine (mg/dL)

Male CrCl = (140 - age in years) x weight (kg) x 1.00 72 x serum creatinine (mg/dL) i) Adequate hepatic function with AST/ALT ≤3x ULN and total bilirubin ≤1.5 x ULN (except subjects with Gilbert syndrome, who can have a total bilirubin ≤3 mg/dL or ≤51.3 μmol/L).

j) Adequate left ventricular ejection fraction of >45% as demonstrated on a Gated Cardiac Blood Pool Scan or echocardiogram.

k) Life expectancy > 3 months. l) Patients of childbearing potential willing to adhere to the following contraceptive precautions. Refer to the Celgene-BMS-986369/CC-99282 Pregnancy Prevention Plan (Appendix 4) for additional guidance.

1. Females of childbearing potential (FCBP) must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG) within 24 hours prior to the start of study treatment.
2. Females must not be breastfeeding.
3. FCBP must use appropriate method(s) of contraception to avoid pregnancy for 23 weeks (30 days plus five half-lives of nivolumab) and 28 days for BMS 986369 post-treatment completion.
4. Men who are sexually active with FCBP must use any contraceptive method with a failure rate of less than 1% per year. They must agree to adhere to contraception for a period of 90 days from the last day BMS-986369 and refrain from donating sperm.
5. Azoospermic males and FCBP who are continuously not heterosexually active are exempt from contraceptive requirements. However, they must still undergo pregnancy testing as described in this section.

m) Written, informed consent.