Hi @krroopeshbharatwaj1 and thanks for your question!
Please have a look at our official guide for using LangChain with Pinecone.
Most of the time when users report this issue, they need to create an environment variable named PINECONE_API_KEY that contains their API key from https://app.pinecone.io.
The LangChain library wraps Pinecone’s client, so is expecting that env var by default.
Hope this helps!
Best,
Zack