Testing Atezolizumab in People 2-17 Years Old With Clear Cell Sarcoma or Advanced Chondrosarcoma

Inclusion Criteria: * Patients must have documented EWSR1/ATF1 or EWSR1/CREB1 translocation or histologically confirmed clear cell sarcoma, documented grade 2 or 3 conventional chondrosarcoma, or documented dedifferentiated chondrosarcoma. The disease must not be curable by surgery * Patients must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded for non-nodal lesions and short axis for nodal lesions) as \>= 20 mm (\>= 2 cm) by chest x-ray or as \>= 10 mm (\>= 1 cm) with computed tomography (CT) scan, magnetic resonance imaging (MRI), or calipers by clinical exam * Patients with newly diagnosed, unresectable, metastatic and measurable clear cell sarcoma, EWSR1/ATF1 or EWSR1/CREB1 translocation, grade 2 or 3 conventional chondrosarcoma, or dedifferentiated chondrosarcoma will also be eligible if they show clinical evidence of disease progression (including history and increasing physical symptoms). On-study documentation will include a physician's rationale that supports evidence of clinical disease progression (i.e., increasing tumor pain) * Age \>= 2 years at the National Cancer Institute (NCI) Clinical Center (\>= 12 years at other participating sites) * Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 (Karnofsky or Lansky \>= 70%) * Life expectancy of greater than 3 months * Absolute neutrophil count \>= 1,000/mcL * Platelets \>= 100,000/mcL * Hemoglobin \>= …