The question isn't answerable, because you haven't defined what 'intelligence' is yet.
That's not just me being pedantic, there is no concrete definition. There is a spectrum of intelligence, not some mystical moment where a beam of light (or big black monolith) suddenly transforms an "unintelligent" species into an "intelligent" one.
Is intelligence defined by the ability to have a conversation with us? That's already possible with many species. We communicate regularly with other species on this planet, including our dogs. We're just incapable of reproducing the communication style of the other, so we operate in a middle ground. We also communicate with all sorts of primates, cetaceans, and so on.
Is intelligence defined by tool use? How much tool use? There are species on this planet that use tools. If you pick a particular tool (fire? nuclear fission? space travel?) as the defining cutoff, were we "unintelligent" the day before we first used it and "intelligent" the day after? If someone teaches a chimpanzee how to start a fire, is that chimp suddenly intelligent? Please don't try that experiment, I don't want to have chimps running around starting fires.
And in the end, yes, this is probably the most important point:
We--as a species--have already encountered non-human intelligence, in the form of Neanderthals, Homo Erectus, and others.
It already happened, by just about any definition, long ago.