I have often heard people say they cannot squat because they have “bad knees”. If you have knee issues you probably need to be doing squats more than you think, but the issue may lie in doing them improperly. Usually in this scenario if you have knee issues you are likely to have overactive quads and week hamstrings, glutes, and adductors. When this happens people tend to have a difficult time letting the weight of their body shift to the heels of their feet while sitting back and down into a squat. Instead, they end up on the balls of their feet, heels off the ground, and the body leaning forward over it’s toes which places unnecessary torque on the knee.
If you have knee issues and are afraid of squatting, I recommend starting with squats onto a box or chair. Set up for your squat and literally sit down onto the box while keeping your chest/torso upright rather than leaning forward. This will allow you to activate the weaker muscles that aren’t used to being engaged in this movement. Once you can perform it with just your own body weight, start holding a dumbbell and increase the weight until you build up strength to perform the squat without the box behind you.