How to Rotate 2D Sprite Towards Moving Direction?

I have been searching all day and reading forums but I can't find a way that works. I'm making a top-down view horror game. When my player walks normally he can look around with the cursor in any direction, but when he wants to run he switches to "tank" controls and rotates toward the running direction. I need something like this.

My player movement script so far:

 public float walkSpeed;
 public float runSpeed;
 public float turnSpeed;
 private Rigidbody2D rb;
 public Camera cam;
 private Vector2 moveDirection;

 void Start()
 {
     rb = GetComponent<Rigidbody2D>();
 }

 void Update()
 {
     ProcessInput();
 }

 void FixedUpdate()
 {
     Move();
 }

 private void ProcessInput()
 {
     float moveX = Input.GetAxisRaw("Horizontal");
     float moveY = Input.GetAxisRaw("Vertical");

     moveDirection = new Vector2(moveX, moveY).normalized;
 }
 void Move()
 {
     if (Input.GetKey(KeyCode.LeftShift))
     {
         //Looking toward movement direction should be applied here
     } else { 
         rb.velocity = new Vector2(moveDirection.x * walkSpeed, moveDirection.y * walkSpeed);

         Vector3 mousePosition = cam.ScreenToWorldPoint(Input.mousePosition);
         Vector2 direction = mousePosition - transform.position;
         float angle = Vector2.SignedAngle(Vector2.right, direction) - 90f;
         Vector3 targetRotation = new Vector3(0, 0, angle);
         transform.rotation = Quaternion.RotateTowards(transform.rotation, Quaternion.Euler(targetRotation), turnSpeed * Time.deltaTime);
     }
 }

Any help is greatly appreciated! Thanks in advance!