No, the CMB was predicted. Like all good hypotheses, the big bang cosmology hypothesis made predictions. Alpher and Gamow are the chaps you need to research, from the late 40s.
Since that time, the existence of the CMB has been proven beyond all doubt. And it was not predicted by other long since dead cosmological models. Such as steady state.
And since that time, the vast majority of those who previously favoured the steady state models, have discarded them as the evidence shows them to be completely wrong.
A tiny minority, who one could consider as being almost fanatical in their belief in the SS models, and/or equally fanatical in their opposition to BB cosmology, continued to try to make their SS models fit the data, with ever more ridiculous mental contortions. Almost in the same way that creationists try to deal with the fossil and dating data.
Those people are now mostly deceased. They were of a certain generation. Nobody is replacing them. SS models are ancient history. Mostly followed by cranks and crackpots, these days. Certain followers were not crackpots, such as Hoyle and the Burbidges, but their attempts to force fit their dead model into the current data certainly came close to putting them in the crackpot category. Others most certainly were within that category - Arp and Lerner, for instance. Lerner always has been, and Arp, sadly, joined him with his quasar and intrinsic redshift woo.
In short, all the evidence backs up the BB model, and all of it rules out other models that do not include expansion. The only people who seem to want to believe in SS models these days, are aging plasma cosmology/ electric universe followers. And that tells you everything you need to know. When you have to start calling on tired light woo to save the day, and galaxies popping out quasars like wet mogwai, you know that you have lost.