The purpose of this study is to evaluate the efficacy, safety, and tolerability of subcutaneous (SC) pembrolizumab (+) berahyaluronidase alfa in Japanese participants with recurrent or metastatic cutaneous squamous cell carcinoma or locally advanced unresectable cSCC. The primary hypothesis is that pembrolizumab (+) berahyaluronidase alfa will result in greater than 10% objective response rate (ORR) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1) as assessed by Blinded Independent Central Review (BICR).