 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. 