Why is my robot not moving although I published in the correct topic?

Course Support ROS Basics In 5 Days (C++)
1 
class MoveTurtlebot {
private:
  ros::Publisher pub;
  ros::NodeHandle nhMove;

public:
  MoveTurtlebot() {
    pub = nhMove.advertise<geometry_msgs::Twist>("/cmd/vel", 1);
  };

  void laser_callback(const sensor_msgs::LaserScanConstPtr &msg) {
    ROS_INFO("I am inside laser_callback");
    ros::Rate rate(1);
    geometry_msgs::Twist move;
    move.linear.x = 0.2;
    move.angular.z = 0.2;
    pub.publish(move);
    rate.sleep();
  }

};

int main(int argc, char **argv) {

  ros::init(argc, argv, "turtlebot_subscriber_node");
  ros::NodeHandle nh;

  ros::Subscriber sub;

  MoveTurtlebot moveTurtlebot;

  sub = nh.subscribe("/kobuki/laser/scan", 1, &MoveTurtlebot::laser_callback,
                     &moveTurtlebot);


  ros::spin();

  return 0;
}

This is the output when I run it:

[ INFO] [1630232440.720399695, 13778.072000000]: I am inside laser_callback
[ INFO] [1630232441.726862869, 13779.073000000]: I am inside laser_callback
[ INFO] [1630232442.745110063, 13780.073000000]: I am inside laser_callback
[ INFO] [1630232443.758681972, 13781.073000000]: I am inside laser_callback
[ INFO] [1630232444.771686571, 13782.073000000]: I am inside laser_callback
[ INFO] [1630232445.805162872, 13783.075000000]: I am inside laser_callback

I really do not understand what I did wrong here, when I try and compile this, the laser_callback is working just fine and I think I have publish inside the correct topic but the thing is my robot is not moving at all. Not even an inch!

So I tried checking if it is not publishing correctly by using the following command:

rostopic echo -n1 /cmd/vel

Here is the output:

linear:
  x: 0.2
  y: 0.0
  z: 0.0
angular:
  x: 0.0
  y: 0.0
  z: 0.2

So, I am publishing it correctly and I dont know what I did wrong in this case.

2

The right topic on the robot is /cmd_vel, not /cmd/vel.