You’re looking to alter the label of a tab field
function my_acf_prepare_field( $field ) {
global $post;
if (get_field('some other field', $post->ID) {
$field['label'] = get_field('some other field', $post->ID);
}
return $field;
}
add_filter('acf/prepare_field/type=tab', 'my_acf_prepare_field');