-  INCLUSION CRITERIA:

               1. Histologically confirmed malignant pleural or peritoneal mesothelioma not
                  amenable to potentially curative surgical resection. The diagnosis will be
                  confirmed by the Laboratory of Pathology, CCR, NCI.

               2. Tumor must have epithelioid histology determined by the Laboratory of Pathology
                  at the NCI. If the patient has biphasic histology, the epithelioid component must
                  be >50%

               3. Have provided archival tumor tissue sample or able to provide newly obtained core
                  or excisional biopsy of a tumor lesion not previously irradiated. Formalin-fixed,
                  paraffin embedded (FFPE) tissue blocks are preferred to slides. Newly obtained
                  biopsies are preferred to archived tissue.

                  Note: If submitting unstained cut slides, newly cut slides should be submitted to
                  the testing laboratory within 14 days from the date slides are cut.

               4. Have disease locally accessible disease to suitable for intratumoral injection of
                  LMB- 100.

               5. Have measurable disease based on RECIST 1.1. Lesions in a previously irradiated
                  area are considered measurable if progression has been demonstrated in such
                  lesions.

               6. Subjects must have received prior immune checkpoint therapy with anti-PD-1/PD-L1
                  inhibitors alone or in combination with anti-CTLA4 blocking antibodies, as well
                  as platinum based chemotherapy.

               7. Age >= 18 years.

               8. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
                  Evaluation of ECOG is to be performed within 28 days prior to initiation of study
                  therapy.

               9. Have adequate organ and marrow function as defined below:

                  System and Laboratory Value

                  Hematological<TAB>

                  hemoglobin >= 9 g/dL(a)

                  absolute neutrophil count >= 1,500/mcL

                  platelets >= 100,000/mcL

                  Hepatic

                  total bilirubin <= 2.5 X institutional ULN OR direct bilirubin <=ULN for
                  participants with total bilirubin levels >1.5 X ULN

                  AST and ALT <= 2.5 X institutional ULN (<= 5 X ULN for participants with liver
                  metastases)

                  Renal

                  Creatinine <=1.5 x ULN OR Measured or calculated(b) creatinine clearance (GFR can
                  also be used in place of creatinine or CrCl) >= 50 mL/min for participant with
                  creatinine levels; > 1.5 X institutional ULN

                  Coagulation

                  International normalized ratio (INR) OR prothrombin time (PT); Activated partial
                  thromboplastin time (aPTT): <=1.5 x ULN unless participant is receiving
                  anticoagulant therapy as long as PT or aPTT is within therapeutic range of
                  intended use of anticoagulants

                  ALT (SGPT)=alanine aminotransferase (serum glutamic pyruvic transaminase); AST
                  (SGOT)=aspartate aminotransferase (serum glutamic oxaloacetic transaminase);
                  GFR=glomerular filtration rate; ULN=upper limit of normal.

                    1. Criteria must be met without erythropoietin dependency and without packed
                       red blood cell (pRBC) transfusion within last 2 weeks.

                    2. Creatinine clearance (CrCl) should be calculated per institutional standard.

              10. Must have left ventricular ejection fraction >50%.

              11. The effects of LMB-100 on the developing human fetus are unknown. For this reason
                  and because ipilimumab is a Category C agent, women of child-bearing potential
                  and men must agree to use adequate contraception (hormonal or barrier method of
                  birth control; abstinence) while on study therapy and for four months after the
                  last dose of study therapy. Should a woman become pregnant or suspect she is
                  pregnant while she or her partner is participating in this study, she should
                  inform her treating physician immediately.

              12. Ability of subject to understand and the willingness to sign a written informed
                  consent document.

        EXCLUSION CRITERIA:

          1. Is currently participating in or has participated in a study of an investigational
             agent or has used an investigational device within 3 weeks prior to initiation of
             study therapy.

             Note: Participants who have entered the follow-up phase of an investigational study
             may participate as long as it has been 3 weeks after the last dose of the previous
             investigational agent. Patients with active devices will be excluded from the study

          2. Has known active CNS metastases and/or carcinomatous meningitis. Participants with
             previously treated brain metastases may participate provided they are radiologically
             stable, i.e. without evidence of progression for at least 4 weeks by repeat imaging
             (note that the repeat imaging should be performed during study screening), clinically
             stable and without requirement of steroid treatment for at least 14 days prior to
             initiation of study therapy.

          3. Has active systemic issues as bleeding diathesis or active infections

          4. Presence of a clinically significant pericardial effusion

          5. Has severe hypersensitivity (>=Grade 3) anti-CTLA4 therapies and/or any of their
             excipients.

          6. Has received prior radiotherapy to the site of local administration

          7. Subjects who have received LMB-100 previously

          8. Has received prior systemic anti-cancer therapy including investigational agents
             within 3 weeks prior to initiation of study therapy. Patients who have received prior
             anti-PD-1/PD- L1 or CTLA4 antibodies are eligible. Any toxicity related to these
             agents must have resolved to grade 1 and they must not be on systemic
             immunosuppressive therapies (physiologic dose of steroids are permitted).

          9. Has received prior radiotherapy to site other than target lesion within 2 weeks prior
             to initiation of study therapy. Participants must have recovered from all
             radiation-related toxicities, not require corticosteroids, and not have had radiation
             pneumonitis. A 1-week washout is permitted for palliative radiation (<=2 weeks of
             radiotherapy) to non-CNS disease.

         10. Has not recovered from all AEs due to previous therapies to <=Grade 1 or baseline.
             Participants with <=Grade 2 neuropathy may be eligible. If participant received major
             surgery, they must have recovered adequately from the toxicity and/or complications
             from the intervention prior to initiation of study therapy.

         11. Has received a live vaccine within 30 days prior to initiation of study therapy.
             Examples of live vaccines include, but are not limited to, the following: measles,
             mumps, rubella, varicella/zoster (chicken pox), yellow fever, rabies, Bacillus
             Calmette-Guerin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injection
             are generally killed virus vaccines and are allowed; however, intranasal influenza
             vaccines (e.g., FluMist(R)) are live attenuated vaccines and are not allowed.

         12. Is receiving therapeutic anti-coagulation. Patients receiving prophylactic
             anticoagulation may be eligible if in the opinion of the study team, anti-coagulation
             may be stopped during the time of LMB-100 administration and tumor biopsies

         13. Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy
             (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of
             immunosuppressive therapy within 7 days prior to initiation of study therapy.

         14. Has active autoimmune disease that has required systemic treatment in the past 2 years
             (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive
             drugs). Replacement therapy (e.g.. thyroxine, insulin, or physiologic corticosteroid
             replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a
             form of systemic treatment.

         15. Has a QTcF interval >480 milliseconds

         16. Has a history of (non-infectious) pneumonitis/interstitial lung disease(ILD) that
             required steroids or has current pneumonitis/ILD

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

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

         19. A woman of childbearing potential who has a positive pregnancy test within 72 hours
             prior to initiation of study therapy. If the using a urine test and test positive or
             cannot be confirmed as negative, a serum pregnancy test will be required. Note: in the
             event that 72 hours have elapsed between the screening pregnancy test and the first
             dose of study treatment, another pregnancy test (urine or serum) must be performed and
             must be negative in order for subject to start receiving study medication.

         20. Is pregnant or breastfeeding, or expecting to conceive or father children within the
             projected duration of the study, starting with the screening visit through 4 months
             after the last dose of trial treatment. Pregnant women are excluded from this study
             because LMB-100 + ipilimumab are agents 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 LMB-100 +
             ipilimumab, breastfeeding should be discontinued if the mother is treated with LMB-100
             + ipilimumab. These potential risks may also apply to other agents used in this study.

         21. HIV positive patients will be excluded due to a theoretical concern that the degree of
             immune suppression associated with the treatment may result in progression of HIV
             infection.

         22. Positive for Hepatitis B or C (defined as Hepatitis B surface antigen reactive) or
             known active Hepatitis C virus (defined as HCV RNA detected) infection. or active HBV
             or HCV infection.

         23. Has a known additional malignancy that is progressing or has required active treatment
             within the past 2 years. Note: Participants with basal cell carcinoma of the skin,
             squamous cell carcinoma of the skin, or carcinoma in situ (e.g. breast carcinoma,
             cervical cancer in situ) that have undergone potentially curative therapy are not
             excluded.

         24. Has an active infection requiring systemic therapy.