We know that Kaido was defeated 7 times in the past, and I believe this panels reveals those 7 defeats. Roger and WB are placed a step above Xebec, Shanks, and Oden in this panel, and I believe that’s for more than just strength reasons. Shanks and Oden being a level below those two checks out, but Xebec should be on Roger and Primebeard’s level. I think Roger and WB are placed higher because they both defeated Kaido twice, while the other 3 defeated him once, for a total of 7 defeats.
WB likely beat Kaido in a duel when Kaido was recruited into Rocks, and he probably beat him again when Rocks disbanded
Roger beat Kaido at God Valley and probably some time afterwards since Roger was the top dog after God Valley, and Kaido would be interested in challenging him obviously
Xebec probably defeated Kaido once to recruit Kaido into his crew. Kaido wouldn’t follow Xebec unless Xebec proved he was stronger
Shanks defeated Kaido when Kaido attempted to go to MF to challenge WB one more time. It probably wasn’t an actual fight, but Shanks probably got Kaido to back down by showing that he was superior CoC to him
Oden defeated Kaido when he landed Togen Totsuka and was about to finish him off before the hag intervened