Something I see a lot this time of year is people coming in every morning and going for a run/bike. Don't get me wrong doing something is better than doing nothing. That said it's important to keep balance in the body both in terms of joint mobility and muscular balance across joints. This will keep you injury free long term alongside looking your best. Since you have done the hard part of getting to the gym why not do something that will make a positive lasting effect?
So back to the early morning pavement pounders, what happens often is that they make some great progress in the first 6 weeks or so then it all starts to slow down. Leave it a little longer and the niggles start to creep in, the knees, hips, sometimes lower back. Sounding familiar yet? Most cardiovascular work is a repetitive motion in a single plane (Run straight forward). It's inevitable then that you run (sorry!) into some issues, joints like the hip are designed to move in multiple directions. Likely your hip flexors and quads become dominant but a little immobile. Also glute medius and minimus end up weak and inactive. The result is a small misalignment or strength discrepancy, doesn't sound like a big issue until you continue doing that repetitive motion. Over time this compounds that misalignment which results in pain. Then we start to blame the running, 'it's bad for my knees'. The solution is to balance resistance work and flexibility work alongside your cardio training.
Immediately some people will say that they burn more calories doing their cardio compared to a weights session. You may be right but if you increase your muscle percentage we burn more calories for the same amount of cardio with the thermogenic effect of muscle contraction. Say you do a run at a set speed that burns 500 calories, if you increase your muscle percentage and then run the same distance at the same speed now you burn more than 500 calories.
Muscle is metabolically active so you will burn more calories at rest than previously. The resulting shift makes it easier to keep progress constant but also to finish with a more aesthetic physique.
Move under load, add rotation, lateral movement and single leg work (not all at the same time!) to keep you moving as efficiently as possible.
I'm not saying you should stop your cardio, just find balance with some multi directional resistance work too to make the most of your hard work. What are you doing today to make a lasting change?
Building athletic lifestyles