Cho Chikun is really good at living. In this game, he played a lot of “small” looking moves to make sure his groups were thick and alive, or at least to make sure he could live with his weak looking groups. He also doesn’t hesitate to give up a few stones, so long as the majority of a group is alive. My guess is that he’d read out how to live with all of his groups fairly early on, and as such was able to ignore what his opponent thought was a big ko threat and connect up to his “dead” stones in the center.
After the ko-smoke clears and the players are approaching endgame, (say, around move 188) if you work out all of the life or death sequences, all of his groups are alive. (Top left lives in seki, I think.) They may not be worth much, but they’ve got, or can get, two eyes. His strategy, for the most part, was to use his strong groups to push around his opponent’s weak groups and reduce, while relying on the big bottom territory he built to win the game for him.
My counting isn’t great, but it looks like he was ahead by roughly komi, or maybe komi plus a few points, heading towards the endgame. His opponent probably decided that trying to get a second eye at the bottom was his only chance, sine he needed to reduce Cho, and a gote move would lose on points. At move 208, he could respond to the capture by getting the eye in the middle of the board, but went for the bottom and died.
But yeah, pros will play with some horrifyingly weak looking groups, which are somehow alive because of a 20+ move sequence they read out. Look up some Mi Yuting on Ke Jie games if you really want to wonder how all of the weak groups are managing to stay alive.