Inclusion Criteria:

1. ≥ 18 years old at the time of informed consent
2. Ability to provide written informed consent and HIPAA authorization
3. Diagnosis of CMML that is CD4+ and is recurrent or refractory to first line standard of care treatment.
4. Creatinine clearance of ≥ 60 ml/min (or otherwise non clinically significant, per study investigator)
5. ALT/AST < 3 x ULN
6. Bilirubin < 2 x ULN
7. Pulmonary Function Test (PFT) with a DLCO of ≥ 60%. This will not have to be repeated if within 45 days of initial assessment.
8. Adequate echocardiogram with EF of ≥50% This will not have to be repeated if within 45 days of initial assessment.
9. Adequate venous access for apheresis and no other contraindications for leukapheresis

Exclusion Criteria:

1. CD4 negative CMML
2. Pregnant or lactating women. The safety of this therapy on unborn children is not known. Female study participants of reproductive potential (see definition below) must have a negative serum or urine pregnancy test prior to initiation of conditioning chemotherapy, per research sites' clinical policy
3. Uncontrolled active infection necessitating systemic therapy

4. Active hepatitis B or hepatitis C infection. Active hepatitis C is defined as the hepatitis C antibody is positive while quantitative HCV RNA results exceed the lower detection limit

   Note the following subjects will be eligible:

   • Subjects with a history of hepatitis B but have received antiviral therapy and have non-detectable viral DNA for 6 months prior to enrollment are eligible
   • Subjects seropositive for HBS antibodies due to hepatitis B virus vaccine with no signs or active infection (Negative HBs Ag, HBc and HBe Ags) are eligible
   • Subjects who had hepatitis C but have received antiviral therapy and show no detectable hepatitis C virus (HCV) viral RNA for 6 months are eligible
   • If hepatitis C antibody test is positive, then patients must be tested for the presence of antigen by reverse transcription-polymerase chain reaction (RT-PCR) and be hepatitis C virus ribonucleic acid (HCV RNA) negative

5. Concurrent use of systemic glucocorticoids in greater than replacement doses or steroid dependency defined in rheumatological and pulmonary diseases as uninterrupted corticosteroid intake for more than a year at a dosage of 0.3 mg/kg/day or greater, and where the underlying disease worsens on temporary stoppage of steroid therapy, with symptoms of steroids withdrawal (eg, lethargy, headache, weakness, pseudo rheumatism, emotional disturbances, etc) precipitated by the temporary stoppage unless tapering can occur safely without compromising the underlying disease, the withdrawal tolerance and can happen in a timeframe appropriate to enroll in this trial without safety concerns

   Subjects who receive daily corticosteroids in replacement doses can be included in the study. The replacement doses are defined as following:

   1. Hydrocortisone 25mg/day or less
   2. Prednisone 10mg/day or less
   3. Dexamethasone 4mg or less - Note: Recent or current use of inhaled glucocorticoids is not exclusionary, as this route pertains extremely minimal systemic penetration
6. Any previous treatment with any gene therapy products
7. Any uncontrolled active medical disorder that would preclude participation as outlined in the opinion of the treating investigator and/or Principal Investigator
8. HIV infection
9. Subjects who have received or will receive live vaccines within 30 days before the first experimental cell treatment. Inactivated seasonal flu vaccination is allowed
10. Subjects with active autoimmune diseases who need systematic treatments (such as disease modifying agents, corticosteroids and immunosuppressive drugs) during the last year Note: Replacement therapy (thyroxine, insulin or physiological corticosteroid replacement therapy (up to10 mg of oral daily prednisone or equivalent in hydrocortisone and dexamethasone) to treat adrenal dysfunction or pituitary dysfunction) is not considered as systematic therapy. Subjects who need inhalation corticosteroid therapy can be included in this trial. Subjects with vitiligo or in long-term remission of pediatric asthma or allergic diseases can be included in this trial
11. Subjects with a history of mental disorders or drug abuse that may influence treatment compliance
12. Active malignancy not related to CMML that has required therapy in the last 3 years or is not in complete remission. Exceptions to this criterion include successfully treated non-metastatic basal cell or squamous cell skin carcinoma, or prostate cancer that does not require therapy. Other similar malignant conditions may be discussed with and permitted by the Principal Investigator

Eligibility for cd4CAR Infusion

1. Afebrile and not receiving antipyretics, and no evidence of active infection. If fever is attributed to underlying disease, it will not disqualify.
2. Specific organ function criteria for cardiac, renal, and liver function must be similar to initial inclusion values. Tests such as echocardiogram and PFTs need not be repeated if within 45 days of initial assessment
3. Negative pregnancy testing (if applicable)
4. If previous history of corticosteroid chemotherapy, subject must be off all but adrenal replacement doses 3 days before the CD4CAR infusion
5. Planned infusion dose was successfully manufactured and met release criteria