A Phase 1 trial evaluating the STING agonist MK-1454 combined with pembrolizumab in a mixed tumor cohort demonstrated partial responses in 3 head and neck squamous cell carcinoma (HNSCC), 2 anaplastic thyroid carcinoma (ATC), and 1 triple-negative breast cancer (TNBC) patient in the combination arm—with no responses in the MK-1454 monotherapy group (0% ORR). Here, STING1 is linked to neoplasm.