Caesars delayed RC expiration to December 31 awhile back. As of this writing, they are not delaying it further.

You need to earn RCs in some way to avoid expiration on December 31, if you haven't otherwise earned in the past 6 months.

The easiest way to earn RCs is to charge something (even very small) on your Total Rewards credit card. But that's if you have one. If you don't, it's too late. I would advise charging at least $5, because sometimes charges like $1 aren't even run, and you just get credit for the purchase (which you don't want here!)

If you don't have the credit card, you can also earn RCs in other ways. Go here, and scroll down to the part labeled "PARTNERS". Then click "Learn More" for each one.

MGM MLife has extended it to 3/31/21, so your points there won't expire yet.