"Does cardio work your heart and lungs different than say weightlifting/ strength training, or are they the same? I'm assuming its beneficial to have both!"
I think it is beneficial to have both. I am certainly no expert, but I can honestly say that being a runner for most of my adult life I have tried every trick in the book to increase speed, stamina, improve my race times using various diet strategies, or running to the point of exhaustion or injury and not eating right. It was not until I incorporated weight lifting and started making healthy food choices (not just eating less of the same junk I always ate) did I see a vast improvement in my race times.
It all depends on what you like and will stick with. But I believe that if you have those 3 things working together...weights/cardio/healthy food choices...you will see a change in your body not only on the outside, but also your energy levels and over all wellbeing.
Good luck to ya!