First you have to save the data somewhere inside the app. Create a state and use setState to update it. Now that you have the latest data, you can use JSX's magic to display them using map. Example:

<div>
  {this.state.data.map((dataObjectToDisplay) => {
    return (
      <div>
        {/* Include your data in a way you want here, you can also replace the div with any other element (li) */}
      </div>
    );
  })}
</div>

<div>
  {this.state.data.map((dataObjectToDisplay) => {
    return (
      <div>
        {/* Include your data in a way you want here, you can also replace the div with any other element (li) */}
      </div>
    );
  })}
</div>

Here is the explanation for this issue you can refer here,

import React, { Component } from 'react'
import axios from 'axios'

class PostForm extends Component {
    constructor(props) {
        super(props)

        this.state = {
            key: '',
            // Where data will be saved.
            data: [],
        }
        console.log(this.state)
    }

    changeHandler = e => {
        this.setState({ [e.target.name]: e.target.value })
    }

    submitHandler = e => {
        e.preventDefault()
        
        axios
        .get(`http://127.0.0.1:8000/hvals_hash?key=${this.state.key}`)
        .then(response => {
                        // Updating the state to trigger a re-render       
            this.setState({data: response.data});
            console.log(response.data)
        })
        .catch(error => {
            console.log(error)
        })
    }

    render() {
        const { key } = this.state
        
        return (
            <center><div>
                <form onSubmit={this.submitHandler}>
                    <div>
                        <h2> DATE PICKER</h2><br></br>
                        <input
                            type="text"
                            name="key"
                            value={key}
                            onChange={this.changeHandler}
                        />
                        
                    </div>
                    <br></br>
                    <button type="submit">Submit</button>
                </form>
            <div>
{this.state.data.map((dataObjectToDisplay) => {
    return (
    <div>
        {
            <ol>{this.state.data}</ol>
        }
    </div>
    );
})}
</div>
    
            </div></center>
        )
    }
}
export default PostForm

add a state (add an object property to this.state) and inside the submit handler, after getting the response in Axios, use setState({[name of state]: response.data }).

That takes care of updating the state. As for where to display them, it is up to you.

You can copy the code anywhere inside the render method. If u want to display it under the form, paste it inside the div container after the form.

For better controlling of the state, you can check one of the state-management tools like redux or simply use global context and implement routing using react-router –

Credits to @MrCeRaYA