Why do many cells together survive better than one cell alone?

I know that one cell with no ECM is subject to anoikis. That's why in general one cell alone not in its environment is dying.

But are there advantages for a cell to live close to other cells even of the same type (for many types it looks obvious) ? If yes what are they and could you give a reference if it is possible please ?

I don't mean only what evolutionary advantages do cells together have over one cell (which is more simple, and there is a wikipedia about it), but I'm more interested if one wants to culture cells that you find generally in tissues, why is it better to take many of them (because it is better, right ?) ?

To be clearer, my point is that I want to understand the mechanisms of what happens when cells (of the same type) are in community and to understand given those mechanisms the advantages a cell has when it is with other cells rather than alone.

Thanks !

Cells can communicate with each other using chemical signals.

But do you also know about gap junctions? These are tunnels that connect cells in tissues.

Water, ions etc. can travel to and fro.

Or maybe a tight junction can connect cells together to form an an organ. No fluids pass through, which is good: The bladder is an example.