You'd think it would be simple, but my Norwegian Forest Cat is loathe to jump over the 60 cm high fence from carpet to carpet. Currently he will jump out from a covered cat toilet, but I think he is still reticent about the other way. How do I encourage his jumping? We just put it up. It surrounds his food area, toilet and favourite window. We don't want him to use an alternate route through the baby bed, which has a rail to jump over--he has jumped in there at least once. Now he will have an extra area for his own use that is not disturbed by my one-year-old. How do they encourage movie cats?
Cats are more likely to jump up onto something higher, or down onto something lower. Jumping over something as high as a baby gate doesn't seem to be as natural a behaviour for them. I would break it up into two steps. Perhaps you can put something next to the baby gate that he can jump up onto, and then down from there. Maybe later if you remove the "something", he will try it in one go.
He will jump over it if he wants to get to the other side. You might be able to entice him over with food or treats.
But consider that he doesn't want to jump over it. There could be a medical reason why he does not want to jump. For example, he could have arthritis which makes it very painful to jump from heights. Based on his breed, hip dysplasia is another possible source of pain. Some cats are good at hiding pain. He also could simply be overweight which just makes it a struggle to jump over high barriers. I am not saying there is something medically wrong with your cat, but it would be worthwhile to have a veterinarian examine him.