DragCameraMobile.cs

private Vector2 MouseAxis
{
    get { return new Vector2(Input.GetAxis("Mouse X"), Input.GetAxis("Mouse Y")); }
}

if(usePanning && Input.GetKey(panningKey) && MouseAxis != Vector2.zero)
{
    Vector3 desiredMove;

    if (!game2D)
    {
        desiredMove = new Vector3(-MouseAxis.x, 0, -MouseAxis.y);
    }
    else
    {
        desiredMove = new Vector3(-MouseAxis.x, -MouseAxis.y, 0);
    }

    desiredMove *= panningSpeed;
    desiredMove *= Time.deltaTime;
    desiredMove = Quaternion.Euler(new Vector3(0f, transform.eulerAngles.y, 0f)) * desiredMove;
    desiredMove = m_Transform.InverseTransformDirection(desiredMove);

    m_Transform.Translate(desiredMove, Space.Self);
}

Asset RTS Camera Open Source: https://github.com/IsmaelNascimento/RTS_Camera