Inclusion Criteria:

          1. Subject is ≥18 years of age

          2. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.

          3. Must have a documented diagnosis of CLL/SLL requiring treatment (IwCLL Guidelines for
             the Diagnosis and Treatment of CLL). In addition presence of clinically measurable
             disease determined by at least one of the factors listed:

               -  nodal lesion that measures ≥ 1.5 cm in longest dimension (LD) and ≥ 1.0 cm in
                  longest perpendicular dimension (LPD), or

               -  spleen that measures ≥ 14 cm in longest vertical dimension (LVD) with a minimum
                  of 2 cm enlargement, or

               -  liver that measures ≥ 20 cm in LVD with a minimum of 2 cm enlargement, or

               -  peripheral blood B lymphocyte count > 5000/uL

          4. All eligible subjects must be relapsed after or be refractory to >2 prior lines of
             therapy one of which must have included an approved BTK inhibitor.

          5. Must meet the following laboratory parameters:

               1. Absolute neutrophil count (ANC) ≥ 1,500 cells/mm3 or ≥ 1000 cells/mm3 if
                  secondary to bone marrow involvement by disease.

               2. Platelet count ≥ 100,000 cells/mm3 (100 x 109/L) or ≥ 50,000 cells/mm3 (50 x
                  109/L) if secondary to bone marrow involvement by disease.

               3. Serum aspartate transaminase (AST/SGOT) or alanine transaminase (ALT/SGPT) < 3.0
                  x upper limit of normal (ULN).

               4. Serum bilirubin < 1.5 x ULN unless due to Gilbert's syndrome.

               5. Calculated creatinine clearance of ≥ 60 ml/min.

        Exclusion Criteria:

          1. Presence of any significant medical condition, laboratory abnormality, or psychiatric
             illness that would prevent the subject from participating in the study.

          2. Prior allogeneic stem cell transplant (SCT)/bone marrow transplant within 12 months of
             signing the ICD. Subjects who received allogeneic SCT ≥ 12 months before signing the
             ICD may be eligible provided there is no ongoing graft-versus-host disease and no
             ongoing immune suppression therapy.

          3. Subject has received prior CAR-T or other T-cell targeting treatment (approved or
             investigational) ≤ 4 weeks prior to starting CC-99282.

          4. Subject has received prior therapy with CRBN-modulating drug (eg, lenalidomide,
             avadomide/CC-122, pomalidomide) ≤ 4 weeks prior to starting CC-99282.

          5. History of second malignancies with life expectancy of ≤ 2 years or requirement of
             therapy that would confound study results.

          6. Peripheral neuropathy ≥ Grade 2.

          7. History of hypersensitivity to lenalidomide, pomalidomide, thalidomide.

          8. Impaired cardiac function or clinically significant cardiac disease.

          9. Persistent diarrhea or malabsorption ≥ NCI CTCAE Grade 2, despite medical management.

         10. Active disease transformation (ie, Richter's Syndrome)

         11. Uncontrolled/active autoimmune hemolytic anemia or thrombocytopenia