It usually depends on your main fitness goal If your priority is building muscle and getting stronger then weight training should generally come first You want to have the most energy available for lifting because tired muscles can reduce your strength and performance Cardio can be done afterward without taking as much away from your strength workout.
If your main goal is improving cardiovascular endurance then doing cardio first can make more sense You will be able to give more effort to your running cycling or other cardio activity when you are fresh After that you can complete your weight training with whatever energy you have left.
For people focused on fat loss either order can work The most important factors are your overall calorie balance your diet your training consistency and recovery Doing cardio after weights can be convenient because you can focus on strength first and then finish with cardiovascular work.
I would normally recommend weights before cardio if muscle growth is your biggest goal Strength training requires good energy and concentration Starting with a long cardio session can leave your legs tired and make exercises such as squats lunges and deadlifts feel much harder.
Cardio before weights is not necessarily bad It can actually be useful as a warm up A few minutes of light cycling walking or jogging can raise your body temperature and prepare your muscles for training The key is keeping the warm up easy rather than turning it into a full cardio workout.
If you are training specifically for running then running before weights may be the better choice Your most important activity should usually receive your best effort This helps you improve your running performance while still allowing you to include strength training afterward.
If your goal is improving stamina then cardio before weights can be useful This lets you train your cardiovascular system while you are still fresh You can then use resistance training as the second part of the workout.
You do not have to choose only one type of exercise You can combine cardio and weight training in the same session as long as the total workload is manageable The main thing is making sure that you are not constantly exhausting yourself and preventing proper recovery.