For Bison, you really have to know the matchup, that applies for any character.
The other player’s been practicing their pressure strings and setups for a long time so you have to learn what works against him.
The best thing to do is get someone to be a target dummy, or just to go into practice mode and test things out. Get him to do his default string and see what you can do against it. Remember that after he does 2 reps of cr.LK xx scissors, he’s out of range for another cr.LK, so this is your opening. Bison players know that and vary what they do after the 2nd scissor. For example, they might do raw scissors, or s.MK, or s.HK, headstomp if in the corner, or whatever. See what works against different things. An interesting thing to note, though, is that after the second scissor, your cr.LK can hit him but his won’t hit you if you’re blocking. Other example options for you include s.MP, s.MK, cr.MK, instant tsurugi.
Also learn your blockstrings because you want to be able to stay on him as well as he can stay on you. I like (close) s.LP, s.LP, s.MP, s.LK (wait), delayed hayate. At the range you’re at after the s.LK in this blockstring is finished, he can’t punish the blocked hayate with cr.LK. Just make sure you don’t cancel the s.LK into hayate because you’ll start the hayate from a closer distance and it’ll be unsafe. You can also replace the hayate with a focus attack, instant tsurugi or EX/HP oroshi to punish him if he tries to poke you out of the hayate startup.
Also for that blockstring, you can easily confirm it into a combo if anything hits, and if s.MP scores a counterhit you can go for a sweep knockdown or f+MP for a safe pressure extender. Also can vary it by chaining s.MP or s.LK into oroshi/EX oroshi, doing tick throw/karakusa after the s.LP’s, or throwing in an instant tsurugi or cr.LK at any point.
Also practice anti-airs. Bison’s offense goes up a lot if you let him jump. cr.MK beats most things easily, and pretty much nullifies any crossup attempt except deep ones on your knockdown. If he likes to jump in with j.HP, I find it loses quite easily to fukiage. He isn’t too hard to hit with it due to his high jump arc. But perhaps the best thing to do is just dash under him when you see him jump. A good player won’t jump unless they think they have the right spacing so just dash and remove that spacing. You might be able to punish him on landing, or you might not, but either way he hasn’t gained anything for it. And if he jumps a lot you’ll probably have success going air-to-air with him, Makoto’s air normals pretty much beat his clean as long as you’re vaguely hitting the right buttons for the spacing. Just don’t get greedy and get s.HK/headstomped.
I don’t think it’s really worth spending meter in neutral situations in this matchup. Your EX reversals have some situational uses, but I wouldn’t try too hard to use them defensively, they’re better used offensively if you ask me. Bison’s usually out of range of EX Karakusa during his cr.LK pressure. EX Oroshi can work, but it’s dangerous to look too hard for an opportunity to use it because behavior like that is visible and not too hard to get around.
Bison’s meterless BNB damage is pretty decent but he doesn’t really have big combos. That can be your advantage in this match. If you can keep things neutral until you get meter, then you gain the ability to gain huge damage off of any single poke. So I’m usually conservative with meter and save it for super or FADC, with the occasional EX move if I feel like it. MK Tsurugi into sweep, Fukiage -> HK tsurugi for 250 if I manage to land one.
After you land a sweep you can jump in with j.HK for a safe jump against all of his reversals. Safe jumping is almost always the best option, but HK Tsurugi on his wakeup can also work decently well if you time it to go over him, but you have to be careful to use the correct timing because it varies depending on the setup. For example, you can get the HK Tsurugi setup off a sweep, but you have to time it differently depending on how close he was to you when you swept him. If you were just about right on top of him, you can do: (sweep), whiff f+MP, hold up-forward, slightly delayed HK tsurugi. If you were near max range, you can do: (sweep), whiff f+LK, hold forward a tiny amount, jump forward, delayed HK tsurugi. Both of those will beat backdashes, avoid reversals, and make him block if he’s standing, but you have to be careful if he’s crouching because it’s easy to time it so that it whiffs him crouching. Mix it up with normal crossups/jumpins or EX Tsurugi to force him to block this setup high.