diff --git a/python/llm/example/CPU/LangChain/chat.py b/python/llm/example/CPU/LangChain/chat.py
index b3695199..223529f1 100644
--- a/python/llm/example/CPU/LangChain/chat.py
+++ b/python/llm/example/CPU/LangChain/chat.py
@@ -30,7 +30,11 @@ def main(args):
     
     question = args.question
     model_path = args.model_path
-    template ="""{question}"""
+    # Below is the prompt format for LLaMa-2 according to 
+    # https://huggingface.co/meta-llama/Llama-2-7b-chat-hf
+    # If you're using a different language model, 
+    # please adjust the template according to its own model card.
+    template = """<s>[INST] <<SYS>>\n    \n<</SYS>>\n\n{question} [/INST]"""
 
     prompt = PromptTemplate(template=template, input_variables=["question"])
 
diff --git a/python/llm/example/GPU/LangChain/chat.py b/python/llm/example/GPU/LangChain/chat.py
index 96df015f..4191c8ea 100644
--- a/python/llm/example/GPU/LangChain/chat.py
+++ b/python/llm/example/GPU/LangChain/chat.py
@@ -30,7 +30,11 @@ def main(args):
     
     question = args.question
     model_path = args.model_path
-    template ="""{question}"""
+    # Below is the prompt format for LLaMa-2 according to 
+    # https://huggingface.co/meta-llama/Llama-2-7b-chat-hf
+    # If you're using a different language model, 
+    # please adjust the template according to its own model card.
+    template = """<s>[INST] <<SYS>>\n    \n<</SYS>>\n\n{question} [/INST]"""
 
     prompt = PromptTemplate(template=template, input_variables=["question"])