AWS API Gateway 'Access-Control-Allow-Origin' header is not present - python-3.x

Question

So, like many before me, I'm also facing the CORS error with AWS API gateway+Lambda(python) for a POST request.
Let me explain the Homeworks I did.
Followed the links and got a basic idea of how CORS works.
Tried enabling lambda proxy integration and tried without it as well.
During the manual configuration attempt I added the "Access-Control-Allow-Origin":'*' manually in API gateway method configurations.
At all times my lambda function is set to return the headers like below:
'headers': {
'Access-Control-Allow-Headers': 'Content-Type',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Methods': 'OPTIONS,POST,GET'
}
Postman is working fine as it worked for most of the people who had issues.
When I check the network traffic in chrome, I get the 'Access-Control-Allow-Origin': '*' as part of the header for OPTIONS. But when POST request has none of these headers I have added in the lambda.
The destination page is hosted in my local and AWS Amplify and both has the same issue.
Few images for reference.
Looking forward to all of your inputs.
Edit:
Adding my lambda code as requested:
import json
import urllib.parse
import boto3
import configparser
import os
import datetime
import json
print('Loading function')
# some more code here...
def lambda_handler(event, context):
logfilename = log(json.dumps(event, indent=2), "Debug")
response = {
'headers': {
'Access-Control-Allow-Headers': 'Content-Type',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Methods': 'OPTIONS,POST,GET'
},
"statusCode": 200,
"body": "{\"result\": \"Success.\"}"
}
return response

Answer 1

You need to add "Secure; SameSite=None" to the cookie you send with the lambda response and add withCredentials: true to your axios request.
Important! The cookie will not be accessible with JS inside you app (as it is httpOnly one). But it will be added to external HTTP requests (execute with axios withCredentials: true)