This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Pembrolizumab is 
Select and explain. 
A. CTLA4 inhibitor, B. Monoclonal antibody against PDL1 receptor, C. Monoclonal antibody against PD1 ligand, D. Monochonal antibody against CDK416
B: Monoclonal antibody against PDL1 receptor
Answer: B: Monoclonal antibody against PDL1 receptor 
Explanation: Pembrolizumab and Nevolumab are monoclonal antibodies against PDL1 receptor used in BRAF -ve malignant melanoma.