Lenvatinib and Pembrolizumab in People With Advanced Soft Tissue Sarcoma

Inclusion Criteria: * Male or female age ≥18 years at time of informed consent * Be willing and able to provide written informed consent/assent for the trial * Be willing to comply with treatment protocol * Availability of archival tissue for correlative studies; either a paraffin block or at least 20 unstained slides are acceptable * Patients must have a metastatic and/or unresectable soft tissue sarcoma as below: * Cohort A: Leiomyosarcoma * Cohort B: High grade undifferentiated pleomorphic sarcoma * Cohort C: Vascular sarcomas (including angiosarcoma and epithelioid hemangioendothelioma) * Cohort D: Other soft tissue sarcomas (including synovial sarcoma and malignant peripheral nerve sheath tumor * Cohort E: Bone sarcomas (including osteosarcoma and chondrosarcoma) * Subjects must have had at least 1 but not more than 3 prior lines of systemic therapy (e.g. chemotherapy, immunotherapy, targeted or biological therapy); patients who decline the standard of care first-line systemic therapy will be eligible for this trial. Prior adjuvant therapy will not count provided it was completed more than 6-month previously. * Presence of measurable disease per RECIST v1.1. Target lesions must not be chosen from a previously irradiated field unless there has been radiographically and/or pathologically documented tumor progression in that lesion prior to enrollment.Where and when possible, target lesions will not be chosen as the biopsy lesion. * Must have a performance statu…