Cats basically only meow at humans.
While many humans communicate with one another through chit-chat or emoji-filled texts, cats primarily interact with fellow felines through scent or touch. But when a cat wants to convey a message to its human (e.g., “Where is my dinner?!”), they may meow for attention. However, as common as it is for cats to meow at humans, they rarely meow at other members of their own species.
That isn’t to say cats never meow at other cats; newborn kittens may meow at their mothers to express hunger or other discomfort. But as cats get older, they realize physical touch and chemical pheromones are most effective for communicating with other cats. They tend to save all that meowing for us humans, as we’re less adept at picking up their physical and olfactory cues.