Estou com erro ao utilizar o findViewById em um fragment

Quando vou executar o App ele Fecha!

package com.example.myapplication.Fragments;

import android.os.Bundle;

import androidx.fragment.app.Fragment;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ImageButton;

import com.example.myapplication.R;

/**

• A simple {@link Fragment} subclass.
  */
  public class CaoFragment extends Fragment {

  private ImageButton buttonCao;

  public CaoFragment() {

  }
  
  <a class="mention" href="/u/override">@Override</a>
  
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
  
  Bundle savedInstanceState) {
  

  View view = inflater.inflate(R.layout.fragment_cao, container, false);
   buttonCao = view.findViewById(R.id.buttonCao);
   return view;
  

  }
  }

Erro
at com.example.myapplication.Fragments.CaoFragment.onCreateView(CaoFragment.java:30)