Show how many people added product in their current cart.

noOfPeopleAddedThisInCart.php

<?php
function show_no_of_people_added_in_cart(){
    global $wpdb, $product;
    $in_basket = 0;
    $wc_session_data = $wpdb->get_results( "SELECT session_key FROM {$wpdb->prefix}woocommerce_sessions" );
    $wc_session_keys = wp_list_pluck( $wc_session_data, 'session_key' );
    if( $wc_session_keys ) {
        foreach ( $wc_session_keys as $key => $_customer_id ) { 
            // if you want to skip current viewer cart item in counts or else can remove belows checking
            if( WC()->session->get_customer_id() == $_customer_id ) continue;
            
            $session_contents = WC()->session->get_session( $_customer_id, array() );
            $cart_contents = maybe_unserialize( $session_contents['cart'] );
            if( $cart_contents ){
                foreach ( $cart_contents as $cart_key => $item ) {
                    if( $item['product_id'] == $product->get_id() ) {
                        $in_basket += 1;
                    }
                }
            }
        }
    }

    if( $in_basket ) 
        echo '<a class="in-basket">' . sprintf( __( '%d people have this in their cart', 'text-domain' ), $in_basket ) . '</a>';

}

add_action( 'woocommerce_after_shop_loop_item_title', 'show_no_of_people_added_in_cart', 11 );
add_action( 'woocommerce_single_product_summary', 'show_no_of_people_added_in_cart', 21 );