Unless you have a treadmill or similar at home to dust off and use, track or trail running is a free alternative for endurance exercise. I always advise against true road-running unless you have no history or family history of lower joint issues.
As we have oft repeated, endurance exercise is worth doing once weekly if you do two other days of calisthenics (which also have endurance components). Although many refer to running as "cardio," it does little or nothing for heart functioning unless it includes HIIT, such as sprints.
Some good advice: How to take up running
Related, 10,000 steps: Not quite magical when it comes to weight. Walking is great to maintain mobility especially in the elderly, but it does nothing for the heart and certainly nothing for losing fat. Quite enjoyable, though. Walks are great, with friends, spouse, whatever.