Are you talking about "Black people", or are you talking about people with dark skin? Those are two completely different things.
Skin color is controlled by just a few genes, and dark skin in one population can be the result of completely different genes than dark skin in another population. The fact that two people from different populations both have dark skin doesn't mean they're related in any way whatsoever.
Usually when someone talks of "Black people", they're speaking of the social construct that groups together everyone descended from Sub-Saharan African groups. Even though it's not a scientifically objective or meaningful grouping, it has a clear defined meaning in use, and certainly isn't meant to include completely unrelated people from other continents who just happen to have dark skin even though they don't have any shared ancestry.
Literally all of that is wrong.
Outside of isolated pockets, the "Negritos" of the Philippines were almost entirely replaced by mainland Asian immigrants about 4,000 years ago. The average Filipino has 90% east Asian DNA, 5% European DNA, and just 3% "negrito" DNA. They're not light because of Spanish colonial rule and admixture, they're light because of invasions from other parts of Asia that came much, much earlier.
The actual Negritos, who were already a tiny population when the Spanish got to the islands, lived primarily in remote mountain areas and didn't really interact with or admix with Spaniards at all.
On top of that, the Aeta people who are called "Negritos" are not African. They're descended from the Oceania genetic line also found in Papua New Guinea, Australia, and pockets of indigenous populations of some of the coastal areas of Asia. They do have several somewhat African-like features, but genetically they turn out to be most closely related to South Indians, not Africans.