modal-example-focus.html

<button class="btn btn-primary" (click)="defaultModal.show()">Default Behavior</button>
<ng-template nzbModal #defaultModal="nzbModal">
  <!-- same as data-focus="true" -->
  <div class="modal fade" tabindex="-1">...</div>
</ng-template>

<button class="btn btn-primary" (click)="noFocusModal.show()">Focus = false</button>
<ng-template nzbModal #noFocusModal="nzbModal">
  <div class="modal fade" tabindex="-1" data-focus="false">...</div>
</ng-template>