Unable to add X-forwarded-for header in https api gateway

You can find a good explanation here. The summary is that, x-forwarded-for was a de-facto-standard and now the standard header is forwarded. If the request already contains x-forwarded-for header, API Gateway will put it in Forwarded header. But still Load Balancer uses x-forwarded-for header. So if you look at your incoming request after API-Gateway and Load Balancer, you will see the IP address of your API Gateway in x-forwarded-for header and the IP addresses of you client in Forwarded header.