The count of cod points isn't shared for each platform so you need to specify a platform, I'm not sure why the title is asked
The API call is
https://my.callofduty.com/api/papi-client/inventory/v1/title/{{title}}/platform/{{platform}}/gamer/{{username}}/currency
And the result is (2900 is my current count on my account)
{
"status": "success",
"data": {
"codPoints": 2900
}
}