Pembrolizumab in Treating Patients With Rare Tumors That Cannot Be Removed by Surgery or Are Metastatic

Inclusion Criteria: * Be willing and able to provide written informed consent/assent for the trial * Have measurable disease based on RECIST 1.1 or irRECIST; only cohort 9 and 10 can have evaluable disease (non-measurable lesions); tumor lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions; patients may have bone metastatic disease evaluable according to tumor evaluation criteria best suitable and accepted for the tumor type evaluated * Have one of the following advanced (unresectable and/or metastatic) solid tumor indications that has progressed following standard therapies, where standard therapies are available: * Squamous cell carcinoma of the skin * Small cell malignancies of non-pulmonary origin * Adrenocortical carcinoma * Medullary renal cell carcinoma * Carcinoma of unknown primary * Penile carcinoma * Vascular sarcoma * Germ cell tumor * Paraganglioma-pheochromocytoma * Other rare tumors (except those tumor types listed in exclusion) * Have failed prior treatment within 6 months of consent date * Have biopsiable disease; subjects must have at least one lesion amenable to biopsy; tumor lesions used for biopsy should not be lesions used as target lesions; in cohort 9: paraganglioma-pheochromocytoma or cohort 10, where there is prominent bony disease, biopsies may not be possible due to the nature of the disease * Be willing to provide archival tissue; if archival tissue is…