Don't recommend using iframes, but using CB Content Module with substitutions to render out specifically whatever content you're wanting. See the below for substitution usage information.
www.joomlapolis.com/documentation/279-community-builder/tutorials/18353-using-substitutions-throughout-cb
If you want a profile canvas box like Connections and Connection Management uses now you could use the below.
Code:
<div class="cbCanvasBox cbCanvasBoxSm img-thumbnail">
<div class="cbCanvasBoxTop bg-muted">
<div class="cbCanvasBoxBackground">
[cb:userfield field="canvas" reason="list" /]
</div>
<div class="cbCanvasBoxPhoto cbCanvasBoxPhotoLeft text-left">
[cb:userfield field="avatar" reason="list" /]
</div>
</div>
<div class="cbCanvasBoxBottom bg-default">
<div class="cbCanvasBoxRow text-nowrap text-overflow">
[cb:userfield field="formatname" reason="list" /]
</div>
</div
</div>
Ensure CB Content Module is configured to output CBs template CSS or the above won't be styled.