JTX-2011 Alone and in Combination With Anti-PD-1 or Anti-CTLA-4 in Subjects With Advanced and/or Refractory Solid Tumors

Inclusion Criteria:

   1. Must be willing and able to participate and comply with all trial requirements and
   able to provide signed and dated informed consent prior to initiation of any trial
   procedures

   2. Evaluable or measurable disease, according to Response Evaluation Criteria in Solid
   Tumors (RECIST) v1.1 criteria, and meet the requirements for the intended study cohort

   3. Male or Female ≥ 18 years of age

   4. Have an Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-1.
   Subjects with ECOG 2 may be considered for enrollment in Parts C, D, F, and H if
   approved by Medical Monitor

   5. Have a predicted life expectancy of ≥ 3 months

   6. Have laboratory values (obtained ≤ 28 days prior to first infusion day) in accordance
   with the study protocol

   7. If medical history of the following, case should be reviewed by the Medical Monitor:
   prior biliary tract disorders (as based on Hepatobiliary SOC high level terms of:
   obstructive bile duct disorders, hepatic vascular disorders, structural and other bile
   duct disorders) or portal hypertension and/or hepatic vascular disorders

   8. Women of child-bearing potential (WOCBP) must have a negative serum pregnancy test at
   screening and a negative urine pregnancy test prior to administration of each dose of
   JTX-2011

   9. WOCBP and males with partners of child-bearing potential must agree to use adequate
   birth control throughout their participation and for 5 months following the last study
   treatment

Exclusion Criteria:

   1. Receiving concurrent anti-cancer treatment (excluding radiation therapy), either
   approved or investigational

   2. Have refused standard therapy

   3. Have received anti-cancer therapies listed below within the specified timeframe, or
   who have ongoing toxicity from prior therapy > Grade 1 according to the Common
   Terminology for Adverse Events (CTCAE). Exceptions to this are: > Grade 1 toxicities
   which in the opinion of the Investigator should not exclude the subject (e.g.
   alopecia, Grade 2 neuropathy, hypo- or hyperthyroidism or other endocrinopathies that
   are well-controlled with hormone replacement) and are approved by the Medical Monitor.

      1. Have received biologic therapy, including immunotherapy, < 28 days prior to C1D1;

      2. Have received CAR-T therapy;

      3. Have received chemotherapy < 21 days prior to C1D1, or < 42 days for mitomycin or
      nitrosoureas;

      4. Have received targeted small molecule therapy < 14 days prior to C1D1;

      5. Have undergone organ transplantation including allogeneic or autologous stem-cell
      transplantation, at any time;

   4. Have undergone a major surgery (excluding minor procedures, e.g. placement of vascular
   access, biopsy, etc.) < 6 months prior to the first day of study treatment, C1D1

   5. Have a history of intolerance, hypersensitivity, or treatment discontinuation due to
   severe immune adverse events on prior immunotherapy, or documented presence of
   neutralizing anti-drug antibody to nivolumab, ipilimumab, or pembrolizumab. Subjects
   who discontinued prior immunotherapies for immune-related adverse events that are
   well-controlled with appropriate treatment may be enrolled if approved by the Medical
   Monitor.

   6. Have a diagnosis of immunodeficiency, either primary or acquired, or treatment with
   systemic steroids or any other form of immunosuppressive therapy within 7 days prior
   to C1D1. Exception: inhaled or topical steroids and adrenal replacement doses are
   permitted in the absence of active autoimmune disease as well as a one-time dose of
   immunosuppressive agents used prophylactically for contrast allergies

   7. Have any active disease requiring systemic immunosuppressive treatment

   8. Have known severe intolerance to or life-threatening hypersensitivity reactions to
   humanized monoclonal antibodies or intravenous immunoglobulin preparations; any
   history of anaphylaxis; prior history of human anti-human antibody response; known
   allergy to any of the study medications, their analogues, or excipients in the various
   formulations of any agent

   9. Are symptomatic or have uncontrolled brain metastases, leptomeningeal disease, or
   spinal cord compression not definitively treated with surgery or radiation (brain
   metastases that are stable and asymptomatic, either treated or untreated, will be
   allowed)

10. Have current second malignancy at other sites, which requires treatment, or in the
   judgement of the Investigator, may require treatment within the next year. Concurrent
   malignancies that do not require treatment and are clinically stable are allowed. A
   past history of other malignancies is allowed as long as the subject is not receiving
   specific treatment other than hormonal therapy, and, in the judgement of the
   Investigator, is unlikely to have a recurrence.

11. Have active and clinically relevant bacterial, fungal, or viral infection, including
   known Hepatitis A, B, or C or human immunodeficiency virus (HIV) (testing not
   required)

12. Have received live vaccines within past 30 days (inactivated vaccines are allowed;
   seasonal vaccines should be up to date prior to first infusion day)

13. Women who are pregnant or breastfeeding

14. Have experienced symptomatic cardiac disease that is unresponsive to surgical or
   medical management

15. Have any medical or social condition that, in the opinion of the Investigator, might
   place a subject at increased risk, affect compliance, or confound safety or other
   clinical trial data interpretation