 This is a Phase II trial to determine the efficacy and safety of stereotactic body radiation therapy SBRT and in situ oncolytic virus therapy used as a window of opportunity treatment before pembrolizumab in patients with metastatic triple negative breast cancer TNBC and metastatic non-small cell lung cancer NSCLC. In situ oncolytic virus therapy will consist of adenovirus-mediated expression of herpes simplex virus thymidine kinase ADVHSV-tk plus valacyclovir therapy. 