900MYA we had a common ancestry with Choanoflagellates (non-animal eucaryotes)

The choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. As the name suggests, choanoflagellates (collared flagellates) have a distinctive cell morphology characterized by an ovoid or spherical cell body 3-10 µm in diameter with a single apical flagellum surrounded by a collar of 30-40 microvilli (see figure). Movement of the flagellum creates water currents that can propel free-swimming choanoflagellates through the water column and trap bacteria and detritus against the collar of microvilli where these foodstuffs are engulfed. This feeding provides a critical link within the global carbon cycle, linking trophic levels. In addition to their critical ecological roles, choanoflagellates are of particular interest to evolutionary biologists studying the origins of multicellularity in animals. As the closest living relatives of animals, choanoflagellates serve as a useful model for reconstructions of the last unicellular ancestor of animals.

Choanoflaggelate genomes indicate that they have ancient genes for cell to cell adhesion.  They also benefitted from incorporation of certain bacteria into their cells to provide the energy for function.  There are at least 20 lineages of multicellularity, of which animals are only one but it is the one we will be following as it leads to the development of humans.  Fungi are more closely related to animals than plants.  Choanoflaggelates sit between fungi and metazoa on the phylogenetic tree.

For more information see 

https://www.sciencedirect.com/topics/immunology-and-microbiology/choanoflagellate

https://www.ibiology.org/ecology/choanoflagellates/