Finally I got the solution

I have a custom payment method that uses the cc-form to take credit card payments with and without 3dsecure. After placing order with 3dsecure, I am re-directing to 3dsecure page as normal, but on returning from 3dsecure, I am re-directed to the home page with "Invalid Form Key. Please refresh the page why because in Magento 2.3 core payment methods are using CsrfAwareActionInterface for each controller."

So now i have implemented same thing in my custom payment method as below

use Magento\Framework\App\CsrfAwareActionInterface;
use Magento\Framework\App\Request\InvalidRequestException;
use Magento\Framework\App\RequestInterface;

class CustomPaymentResponse extends \Magento\Framework\App\Action\Action implements CsrfAwareActionInterface

/**
* @inheritDoc
*/
public function createCsrfValidationException(
RequestInterface $request
): ?InvalidRequestException {
return null;
}

/** <br>
 * @inheritDoc <br>
 */ <br>
public function validateForCsrf(RequestInterface $request): ?bool <br>
{ <br>
    return true; <br>
}

Finally I got the solution

I have a custom payment method that uses the cc-form to take credit card payments with and without 3dsecure. After placing order with 3dsecure, I am re-directing to 3dsecure page as normal, but on returning from 3dsecure, I am re-directed to the home page with "Invalid Form Key. Please refresh the page why because in Magento 2.3 core payment methods are using CsrfAwareActionInterface for each controller."

So now i have implemented same thing in my custom payment method as below

use Magento\Framework\App\CsrfAwareActionInterface;
use Magento\Framework\App\Request\InvalidRequestException;
use Magento\Framework\App\RequestInterface;

class CustomPaymentResponse extends \Magento\Framework\App\Action\Action implements CsrfAwareActionInterface

/** 
 * @inheritDoc
 */
public function createCsrfValidationException(
    RequestInterface $request 
): ?InvalidRequestException {
    return null;
}

/**
 * @inheritDoc
 */
public function validateForCsrf(RequestInterface $request): ?bool
{
    return true;
}

Note : you can get reference from core module. Here is the core file path vendor\magento\module-authorizenet\Controller\Directpost\Payment\BackendResponse.php.