Description
I will introduce several recent developments in analytical studies of cosmological correlators with massive exchanges, with an emphasis on the canonical objects called family trees. These family trees are well-defined hypergeometric functions to which an arbitrary massive tree graph can be reduced. I will discuss their analytical structures, differential equations, as well as generalizations to various degenerate kinematics including folded trees and loop integrands, which are important for phenomenological applications in cosmological collider physics.