confused...

It depends on the intensity of the workout session. I like to run and most of my running are easy runs, but sometimes I do tempo or pace runs and I need a recovery day so that my legs can rest. Though on the days that I don't run, I can do other things like cardio or strength training.

You need 48 hours rest after a weight training session ( on those body parts) If you work all your muscles in your workout, which tends to be what beginners do, then take 2 days off. If you are training arms & back today, then you shouldn't work them for 48 hours, but you can do legs. So if you've just worked your legs & need 48 hours rest, cardio on those 2 days is not advised.
You should alternate your cardio & weight training days & every 3 or 4 days should be a day of rest so that your muscles can repair themselves.

Generally, rest days between cardio workouts are not needed unless they are very intense. Moderate level cardio workouts every day are fine and are good for you. They increase the efficiency of your heart and lung function and your body's use of oxygen. The breaks with weight training are needed because (if you're doing to properly) there is actually low level strain and damage that is being done to the muscle and ligaments. The rest time allows your body to go in and fix this, during which process additional muscle will be added as a way to compensate for the work load being put on them - that's why you gain muscle with weight work. Overworking the muscles be working the same ones hard every day will lead to damage that the body can't repair fast enough or properly. You can weight work every day, but only as someone else suggested by rotating which muscles you're working each day.

I didn't read the other replies, so I apologize in advance if I'm repeating...

I was told you should never work the same muscles two days consecutively. What the trainer who set me up with my regime at my gym suggested is a three day cycle. Day 1, I do 30-45mins cardio and strength training with my arms, Day 2, 30-45 cardio and strength training on my legs, Day 3, 45-60 mins cardio. Now, if I'm only getting to the gym 4 days that week instead of my planned 6, I skip the straight cardio days and just alternate the arms and legs days.