Is biking cardio or strength?

Good day everyone, I have a question that's been lingering in my mind for quite some time now. I've heard different opinions on whether biking is primarily a cardio exercise or a strength-building activity. Some say it's an excellent way to get your heart rate up and improve cardiovascular health, while others argue that the resistance and effort required during cycling can help build muscle strength, particularly in the legs. So, I'm curious to know your thoughts on this. Is biking primarily a cardio exercise that enhances cardiovascular fitness, or is it more of a strength-training activity that helps build and tone muscle? I'd love to hear your insights and experiences with biking and how it has impacted your fitness goals. Thank you in advance for sharing your thoughts!