Tissue and Hematopoietic/Mesenchymal Stem Cell for Humanized Xenograft Studies in Melanoma and Squamous Head and Neck Cancer

Inclusion Criteria: 1. Biopsy proven incurable melanoma or incurable HNSCC amenable to have biopsy and/or surgical resection of either the primary and/or locoregional metastatic site, at the University of Colorado Hospital. 2. Age ≥ 21 years old per NCI/NIH guidelines 3. Eastern Cooperative Oncology Group (ECOG) performance status of 0. 1, or 2 4. Adequate bone marrow, hepatic and renal function: * Absolute neutrophil count ≥ 1,500/µL. * Platelets ≥ 100,000/µL. * Hemoglobin ≥ 9.0 g/dL. * Creatinine ≤ 1.5x upper limit of normal (ULN) or calculated creatinine clearance ≥ 60 mL/min. * Total bilirubin ≤ 1.5x ULN. * Aspartate Aminotransferase (AST)/Alanine Aminotransferase ( ALT) ≤ 2x ULN. 5. Measurable disease according to Response Criteria in Solid Tumors (RECIST) version 1.1. 6. O2 saturation ≥= 93% at room air. 7. Ability to understand and willingness to sign a written informed consent document Exclusion Criteria: 1. Contraindication (absolute or relative) to granulocyte colony-stimulating factor (G-CSF) filgrastim usage: * known hypersensitivity to E coli-derived proteins' filgrastim, or any other component of the product. * Sickle cell disorders. * Clinically significant and active lung hemorrhagic or inflammatory disease, including but not limited to chronic obstructive pulmonary disease (COPD), autoimmune disease, and alveolar hemorrhage; or hypoxemia of any etiology requiring oxygen. * Clinically significant splenomegaly or splenic metastases; history of splenic rupture, recent splenic trauma or other clinically significant splenic disease that increases the risk of splenic rupture. 2. Clinically significant and active malignancy other than incurable melanoma or head and neck squamous cell cancer. 3. Known hepatitis B or C, or HIV.