Welcome back, Commander. You're about to play XCOM 2 as it's meant to be played.
XCOM Enemy Unknown seemed on the surface to be a game about leading a rag-tag band of hardnuts as they battled wave after wave of invading aliens, but it was really, underneath all that, a game about managing failure. It was about fighting infinite aggression with finite resources, and about making do as best you could in a war in which every loss was both permanent and costly.
XCOM 2 came out earlier this month to wide acclaim, but it's also generally considered to be a good deal trickier than the previous title in the series. Thankfully, and just like in the original modern reboot of XCOM, there's a host of console commands and cheat codes that you can make use of if you've hit a total brick wall in your progress.