Inline template with Drupal 8 and Twig

Example 1. Basic inline template

    $output[] = [
      '#type' => 'inline_template',
      '#template' => '{{ yourvar }}',
      '#context' => [
        'yourvar' => 'The Value',
      ],
    ];
    return $output;

Example 2. Display a basic value and a raw HTML

    $output[] = [
      '#type' => 'inline_template',
      '#template' => '{{ yourvar }} {{ yourhtml | raw }}',
      '#context' => [
        'yourvar' => 'Your Var',
        'yourhtml' => '<span style="color:red;">Your HTML</span>',
      ],
    ];
    return $output;