Not everyone can, or wants, to squat. It might be down to mobility, an injury, or a preference, but you perhaps want to build lower-body strength and work your hips, glutes, quads and hamstrings hard, without repeatedly bending your knees and moving up and down. You still can.
Enter a variation on the popular wall sit that I wish all my clients would do as they get older. It's low-impact, which is great news if your knees don't get on with front squats, back squats, or any other squat variation for that matter.