The overall goal of this study is to develop a pre-clinical platform of melanoma and head and neck squamous cell cancer that will allow the investigators to learn more about these diseases and discover better and more individualized treatments.

The main objective of this study is to establish a humanized animal model. Investigators will consent patients who have melanoma and head and neck squamous cell cancer (HNSCC) and agree to take part in this research study. They will obtain peripheral hematopoietic stem cells (HSC), blood and tumor tissue at baseline from blood and tumor samples from these patients for use in establishing tumor explants in humanized mice. Therapy results on humanized mice will be correlated with existing or newly acquired efficacy results from those same immune-based or other therapies in patients. A secondary objective is to identify pharmacodynamic markers associated with each drug and biomarkers for evidence of efficacy or lack of thereof. Where possible, subjects receiving therapy with FDA-approved drugs of interest will be asked to provide sequential blood and tumor biopsies to study the molecular and immune events that may occur as a result of drug therapy.

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.

42 days