How to produce markup from a custom views field (FieldPluginBase based) render method in D8?
I can output HTML using my render method. Take a look:

  /**
   * {@inheritdoc}
   */
  public function render(ResultRow $values) {

    $field_abnormal_category = $this-&gt;view-&gt;field['field_abnormal_category']-&gt;original_value-&gt;__toString();

    if($field_abnormal_category == 'No') {
      $field_category_image = $this-&gt;view-&gt;field['field_category_image']-&gt;original_value-&gt;__toString();
    }
    else {
      $field_category_image = '';
    }

    return [
    '#type' =&gt; 'inline_template',
    '#template' =&gt; $field_category_image
    ];

  }