> [!CAUTION]
> **Caution:** This documentation is for Google Ads API **v24** . The latest active version is [**v26**](https://developers.google.com/google-ads/api/reference/rpc/latest/SuggestKeywordThemesResponse.KeywordTheme).

A Smart campaign keyword theme suggestion.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v24/services/smart_campaign_suggest_service.proto)

| Fields ||
|---|---|
| ## `keyword_theme` Union field. A keyword theme. `keyword_theme` can be only one of the following: ||
| ### `free_form_keyword_theme` | `string` A free-form text keyword theme. |
| ### `keyword_theme_constant` | `KeywordThemeConstant` A Smart campaign keyword theme constant. |