PHP Unable to Return curl response - php

Question

I cannot return the response. I successfully tried this request with Postman. The result is in JSON format already, I want to return JSON. If I mess with the header, the error message returned by the api is successfully displayed. The whole point is simply to return the JSON-data, it is retrieved of an API, but the app that I want to display the data in does not support headers, so I'm trying to build an URL which displays the data without any headers needed.
EDIT Solved
Following Phil I've updated my code to:
$url = "https://api.com/data";
$headers = array(
"accept-encoding: gzip",
"cache-control: no-cache",
"connection: keep-alive",
"content-type: application/json",
"Authorization: Bearer superlongkey"
);
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
curl_setopt($curl, CURLOPT_ENCODING, "gzip");
$resp = curl_exec($curl);
curl_close($curl);
$response->getBody()->write($resp);
return $response
Additionally, I had to include the line
curl_setopt($curl, CURLOPT_ENCODING, "gzip");
to decode the data from gzip
$url = "https://api.com/data";
$headers = array(
"accept-encoding: gzip",
"cache-control: no-cache",
"connection: keep-alive",
"content-type: application/json",
"Authorization: Bearer superlongkey"
);
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
$resp = curl_exec($curl);
curl_close($curl);
$response->getBody()->write(json_encode($resp));
return $response
The error I get is
fwrite() expects parameter 2 to be string, boolean given
I've also tried to leave out the fwrite line, but then I get the following error:
Return value of Slim\Handlers\Strategies\RequestResponse::__invoke() must implement interface Psr\Http\Message\ResponseInterface, string returned