Other Exclusion Criteria:

Patients who have had chemotherapy, targeted small molecule therapy, or radiotherapy within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to first dose of trial treatment, or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier.

Patients who are currently participating in or have participated in a study of an investigational agent or using an investigational device within 4 weeks of the first dose of trial treatment.

Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment.

Has had a prior monoclonal antibody within 4 weeks prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from AEs due to agents administered more than 4 weeks earlier. Non-clinically significant adverse events may be considered as an exception after discussion with and approval by the principal investigator.

Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy.

Patients with known active and untreated brain metastases should be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction that would confound the evaluation of neurologic and other adverse events.

History of allergic reactions attributed to compounds of similar chemical or biologic composition to pembrolizumab (MK-3475) and/or rhIL-12 or other agents used in study.

Has an active autoimmune disease requiring systemic treatment within the past 3 months or a documented history of clinically severe autoimmune disease, or a syndrome that requires systemic steroids or immunosuppressive agents. Patients with vitiligo or resolved childhood asthma/atopy would be an exception to this rule. Patients that require intermittent use of bronchodilators or local steroid injections would not be excluded from the study. Patients with hypothyroidism stable on hormone replacement or Sjogren’s syndrome will not be excluded from the study.

Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the patient’s participation for the full duration of the trial, or is not in the best interest of the patient to participate, in the opinion of the treating investigator.

Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.

Patients on any systemic corticosteroid therapy within one week before the planned date for first dose on study would not be eligible. Exception: patients on physiologic replacement doses of corticosteroids are permitted.

Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, interstitial lung disease or active, non-infectious pneumonitis, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.

Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the pre-screening or screening visit through 120 days after the last dose of trial treatment. Pregnant women are excluded from this study because pembrolizumab (MK-3475) is an agent with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with pembrolizumab (MK-3475), breastfeeding should be discontinued if the mother is treated with pembrolizumab (MK-3475). These potential risks may also apply to other agents used in this study.

Has known active Hepatitis B (e.g., HBsAg reactive) or Hepatitis C (e.g., HCV RNA [qualitative] is detected).

Has received a live vaccine within 30 days prior to the first dose of trial treatment.