Androgen Deprivation Therapy (ADT) and Pembrolizumab for Advanced Stage Androgen Receptor-positive Salivary Gland Carcinoma

Inclusion Criteria: * Written informed consent and HIPAA authorization for release of personal health information. NOTE: HIPAA authorization may be included in the informed consent or obtained separately. * Age ≥ 18 years at the time of consent. * Locally advanced, recurrent, or metastatic salivary gland carcinoma that is not amenable to curative surgery or radiation * ECOG Performance Status of 0 or 1 within 28 days prior to registration. * Local, pathologic testing of androgen receptor-positive salivary gland carcinoma will be performed as standard of care. Archival tissue must be available for central confirmation of androgen receptor-positive disease and for correlative studies. AR positivity will be defined according to IHC staining of tumor tissue with at least 20% of tumor staining positive with moderate intensity (1+ or greater). * Measurable disease according to RECIST v1.1 for solid tumors within 28 days prior to registration. * For patients who have been treated with prior therapy, patients must have documented progression of disease on their prior therapy for entry into the study. * Patients with prior chemotherapy, radiation, or surgery as part of curative intent therapy are allowed. Any number of prior lines of systemic therapy is permitted for entry into this study so long as prior therapy did not include anti-androgen therapy or immune checkpoint blockade. * If prior cancer treatment, the subject must have recovered from toxic effects of prior cancer treatmen…