There are several ways to celebrate cultural diversity in global friendships, including sharing traditions and customs, participating in cultural events or festivals, exchanging cultural artifacts or gifts, and learning about each other's cultural heritage. Share your own traditions and customs with your friend, and invite them to participate in cultural events or celebrations from your culture. Similarly, show interest in your friend's cultural background and traditions, and ask them to share stories, recipes, or customs from their heritage. Exchange cultural artifacts or gifts as tokens of friendship and appreciation, and take the opportunity to learn about each other's cultural heritage and history.