Lenalidomide and Obinutuzumab for Previously Untreated CLL

* Main Inclusion Criteria: 1. Clinical and phenotypic verification of B cell CLL or SLL and measurable disease. 2. Prior therapy: no prior CLL therapy. 3. Patients must have progressive disease based on 2008 iwCLL definition with one of the following: * Symptomatic or progressive splenomegaly * Symptomatic lymph nodes, nodal clusters, or progressive lymphadenopathy * Progressive anemia (hemoglobin ≤ 11 g/dL) * Progressive thrombocytopenia (platelets ≤ 100 x 109/L) * Weight loss \> 10% body weight over the preceding 6 month period * Fatigue attributable to CLL * Fever or night sweats for \> 2 weeks without evidence of infection * Progressive lymphocytosis with an increase of \> 50% over a 2-month period or an anticipated doubling time of less than 6 months. * Able to take aspirin (81mg or 325mg) daily, warfarin, low molecular weight heparin, or equivalent anticoagulation as prophylactic medication. * All study participants must be registered into the mandatory Revlimid REMS program, and be willing and able to comply with the requirements of REMS. * Females of childbearing potential (FCBP) must have a negative serum or urine pregnancy test with a sensitivity of at least 50 mIU/mL within 10 - 14 days prior to and again within 24 hours prior to starting Revlimid and must either commit to continued abstinence from heterosexual intercourse or begin TWO acceptable methods of birth control. * Females of reproductive potential must adhere to the scheduled pregnancy testing as required in the Revlimid REMS program. * ECOG performance status of 0-2. * Adequate hematologic function * Adequate renal function * Adequate hepatic function Exclusion Criteria: * Pregnant or breast-feeding women will not be entered on this study due to risks of fetal and teratogenic adverse events as seen in animal/human studies. Women for child-bearing age must obtain a pregnancy test and pregnant or breast feeding females are excluded. * Known hypersensitivity to thalidomide or lenalidomide (if applicable), including development of erythema nodosum or a desquamating rash while taking thalidomide or similar drugs. * Deep vein thrombosis or superficial thrombophlebitis of any cause on current anticoagulation therapy at the time of screening. * Patients who are currently receiving another investigational agent are excluded. * Current infection requiring parenteral antibiotics. * Known seropositive for or active viral infection with human immunodeficiency virus (HIV); or known active infection with hepatitis B virus (HBV) or hepatitis C virus (HCV) based on detectable viral load. Patients who are seropositive because of hepatitis B virus vaccine or passive immunization by intravenous immunoglobulin (IVIG) are eligible. * Active malignancy within the previous 2 years (other than completely resected non-melanoma skin cancer or carcinoma in situ). * Known central nervous system (CNS) involvement by malignancy. * Untreated autoimmunity such as autoimmune hemolytic anemia, or immune thrombocytopenia. * Insufficient recovery from surgical-related trauma or wound healing. * Impaired cardiac function