ICO is a token sale mechanism like other ones, combination of words that means initial coin offering where tokens are launched for public investors to buy. They usually have soft cap and hard cap target and soft target is the minimum needed amount to launch the project and the maximum cap is the maximum needed. There is nothing special about them, we already have IEO which was started by centralized exchanges and later we have IDO that were done on launpads, all these are for raising funds.

If there is bull run buy 2025, I think there is going to be new sales of tokens mechanism but not really the ICO concept due to concerns about scams, so many fake projects raising money without fulfilling and the team ghosting investors after raising large amount of money. Even the other new concept have their own flaws as well, so you need to be careful about them.