MCL1 and head and neck squamous cell carcinoma: Prior studies in cervical cancer, melanoma, medulloblastoma, head and neck squamous cell carcinoma, and pancreatic cancer have evaluated A-1331852, navitoclax, and/or venetoclax in combination with S63845, showing similar improvements in efficacy when co-targeting Bcl-xL and Mcl-1 over Bcl-2 and Mcl-1 (11–13, 44, 45).