• Patients must have pathologically confirmed diagnosis of one of the following:

∙ Pleomorphic liposarcoma

‣ PEComa (perivascular epithelial cell tumor)

‣ Epithelioid sarcoma

‣ CIC-rearranged sarcoma

‣ SEF/LGFMS: Sclerosing epithelioid fibrosarcoma - low grade fibromyxoid sarcoma

• Molecular characterization of the tumor, if available, will be recorded. If no such molecular data are available, note as such.

• Patient should have recurrent or metastatic disease not judged to be curable with other means

• Patients must have progressed (in the opinion of the treating investigator) following the most recent line of therapy. The reason for this progression must be documented, employing tumor measurements when available.

• Definition of Measurable Disease

‣ Measurable disease as per RECIST 1.1. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions for a minimum of 3 months after completion of such therapy

⁃ Patients with treated brain metastases are eligible if follow up brain imaging after CNS-directed therapy shows no evidence of progression at least 4 weeks after the completion of therapy as shown by follow up imaging before study screening

⁃ One to 3 prior lines of therapy are permitted (including neoadjuvant/adjuvant or metastatic/recurrent disease)

⁃ Participants who have AEs due to previous anticancer therapies must have recovered to ≤Grade 1 or baseline. Participants with endocrine-related AEs who are adequately treated with hormone replacement or participants who have ≤Grade 2 neuropathy are eligible. Patients with alopecia and other toxicities considered clinically nonsignificant and/or stable on supportive therapy, as determined by the investigator, are also permitted on study.

⁃ Administration of killed vaccines is allowed

• Age ≥ 18 years of age.

• ECOG Performance Status 0-1 (Karnofsky 70-100)

• Required organ function (specimens to be collected within 14 days of the start of the study intervention)

‣ Adequate hematologic function, defined as:

• Absolute neutrophil count (ANC) ≥ 1,000 cells/mm\^3

∙ Platelets ≥ 100,000 cells/mm\^3

∙ Hemoglobin ≥ 9 g/dl

⁃ Adequate renal function defined, as:

• Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN) (patients with known Gilbert disease who have bilirubin level ≤ 3 x ULN may be enrolled)

∙ AST and ALT ≤3 x institutional ULN

⁃ Adequate cardiac function, defined as: class II or better New York Heart Association (NYHA) Functional Classification.

⁃ For patients with known HIV, HBV, and/or HCV infection \[HIV, HBV, and HCV testing do not need to be performed as part of the study; the below language provides guidelines for inclusivity of patients with known HIV, HBV, and/or HCV infection\]:

• HIV-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months and CD4+ T cell count of at least 350 cell/mm3 are eligible for this trial.

∙ HIV-infected patients with a history of either Kaposi sarcoma or Castleman disease are excluded from this study

∙ HIV-infected patients must not have had an AIDS defining opportunistic infection within the past 12 months

⁃ For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated.

⁃ Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load.