It seems to me that awhile ago Bitcoin owners were being encouraged to move their Bitcoin into Bitcoin Cash in order that they might receive twice as much return from it than if we left it in Bitcoin. Is that still the case?
You must be confused about the fork (you basically create a copy of the coin, and you can change whatever you want to change in the protocol) that happened. People were encouraged to move their BTC (Bitcoin) to a wallet they actually control, so they can claim an equal number of BCH (Bitcoin Cash) when the fork happens. This has already happened so there's nothing you can do anymore, but if you had any BTC in any wallet you own the private keys of prior to August 1, 2017, you may be able to claim an equal number of BCH.
The others have already highlighted that they're different, but it's worth noting that they have no affiliations with each other at all (one can die while the other lives, their prices and supply are completely independent, etc.). I personally believe your money is much safer with BTC.