The goal of this observational study is to learn how tumor tissue and blood samples from patients with sarcomas or metastases can be used to create laboratory models that help researchers study cancer behavior and test new treatments. Participants diagnosed with sarcoma or with bone or lung metastases from solid tumors will donate leftover tumor tissue and blood collected during their regular medical care. These samples will be used in the lab to build 3D models of the tumor, test drugs, and identify genetic and molecular markers. No treatments or procedures will be given as part of the study.