My Subscriber isn't picking up TurtleBot3's scans

edit

Using ROS2 Dashing, running on the Dashing Docker environment, and using Tmux to run multiple nodes in the same console. I setup my TurtleBot3 installation and prepared things for simulation.

I can run

ros2 launch turtlebot3_gazebo turtlebot3_world.launch.py

And this command shows messages being published

ros2 topic echo /scan

But after this I built a node in a separate package, which is unable to subscribe to /scan. This is the MVCE:

void topic_callback(const sensor_msgs::msg::LaserScan::ConstSharedPtr msg)
{
  std::cout << "Got something!" << std::endl;
}

int main(int argc, char *argv[]) {
  rclcpp::init(argc, argv);

  auto node = rclcpp::Node::make_shared("whateverName");
  rclcpp::Subscription<sensor_msgs::msg::LaserScan>::SharedPtr subscription_ = node->create_subscription<sensor_msgs::msg::LaserScan>("/scan", 10, std::bind(&topic_callback, std::placeholders::_1));
  rclcpp::spin(node);
  rclcpp::shutdown();
  return 0;
}

Running this node prints nothing. What am I doing wrong here?