Multiple Relations Trouble I'm having trouble setting entries with multiple relations.
during testing I've hard coded the theme to 1 specific category
{% set themeID = &quot;12309&quot; %}
{% set theme = craft.categories.group('survivorThemes').id(themeID).all() %}

I then set this
{% set survivors = craft.entries.section('authors').includeInRecollection('1').relatedTo({ sourceElement: relatedAssetIds }).orderBy('lastName asc').limit(null).all() %}  
and then a for loop
        {% for survivor in survivors %}
            {% set relatedIds = &quot;&quot; %}






{# this should work but doesn't #}
            {% set entries = 
                craft.entries.section('survivorAssets')
                .relatedTo('and', { targetElement: themeID },{ targetElement: survivor })
                .orderBy('assetOrder')
                .all() 
            %}  

{# this should also work but doesn't #}
            {% set testEntries = craft.entries.section('survivorAssets')
                .relatedTo('and', {targetElement: survivor, field: 'relatedSurvivor'}, {targetElement: themeID, field: 'themes'})
                .orderBy('assetOrder')
                .all()  %}






          &lt;div class=&quot;testing&quot; style=&quot;background:red;color:#fff;padding:30px;margin:30px;&quot;&gt;

            survivor: {{ survivor.title }} &lt;br&gt;

            theme: {{ themeID }} &lt;br&gt;

            ids: {{ relatedIds}} &lt;br&gt;

            total results: {{ entries|length }} &lt;br&gt;

            test total: {{ testEntries|length }} &lt;br&gt;

          &lt;/div&gt;&lt;!-- /.testing --&gt;


                {% if entries|length %}
                    {% set activeClass = &quot; active&quot; %}
                    {% for entry in entries %}
                        {% set relatedIds = relatedIds ~ entry.id %}
                        {% if not loop.last %}
                            {% set relatedIds = relatedIds ~ &quot;,&quot; %}
                        {% endif %}

              more code here
                        
                    {% endfor %}                    
                {% endif %}
                
        more code here
        
        {% endfor %}

In the above loop I expect the entries to have results but I get zero results in my test div.

survivor: Judy Abrams
theme: 12309
ids:
total results: 0
test total: 0

Have confirmed that there should be 3 entries that match the entries or testEntries variable by looking at specific entries in the control panel.
The relatedTo parameter can take an object, an element ID or an array of element objects and/or IDs. In your case the latter is expected so wrapping your arguments in an array should fix the issue:

{% set entries = craft
                .entries
                .section('survivorAssets')
                .relatedTo(['and',{ targetElement: theme },{ targetElement: survivor }])
                .orderBy('assetOrder')
                .all() %}