Why is the key of the left node missing after insertion?

I could not use the Insert_node to insert a node with corresponding key, and I couldn't figure out the problem. Keys is an array of integers I created earlier. Here is the code:

Node* Create_node(int x)
{
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->key = x;
    newNode->left = NULL;
    newNode->right = NULL;
    return newNode;
}
Node* Insert_node(Node** proot, int x)
{
    Node* root = *proot;
    if(root == NULL)
    {
        root = Create_node(x);
    }
    return root;
}
int main()
{
    Node* root = Create_node(keys[0]);
    Insert_node(&root->left,keys[1]);
    printTree(root);
    return 0;
}