Being a live service title, of course The First Descendant has a Battle Pass. There are rewards you can get from it on the free track, but the best stuff is locked behind the premium option. Since this is a free-to-play title, that's not really too much of a problem, after all, the developers have to eat.
What is potentially more of a problem is that the Battle Pass in The First Descendant can be painfully slow to level up. I almost wish I'd bought the version with 25 level skips. Maybe that's what they were hoping?
In any case, you don't need to buy skips, you can speed up the process of leveling up the Battle Pass, but don't expect to be completing it in hours. Or even days. You'll still have to invest some time.
How to level up The First Descendant Battle Pass quicker
You could just play through the game normally, and you will start to progress through the Battle Pass tiers. But if you do this, it is painfully slow. So slow that, even playing every day, I'm not sure you'd be able to unlock all the tiers.
The trick is to complete the challenges. Similar to some other games and how they handle their respective battle or season passes, there are daily, weekly, and seasonal challenges that will net you a good chunk of XP towards your Battle Pass tiers.
The rewards for completing the challenges naturally scales, with dailies offering the least, weeklies a bit more, and the seasonal challenges, which will probably take most of the season to complete, offer the most.
At least on the lower tiers of the Battle Pass (I haven't got far enough to see if the XP required to level up increases further on yet) three daily challenges will get you up a level. One weekly challenge will also jump you up a whole level. That's two levels per day, and eight levels per week on the challenges.
Some of the challenges will be fairly quick to complete, such as defeating a quantity of enemies with a certain ammo type, for example. Others will take longer, but there is always something you can target to get rattling off those Battle Pass tiers a bit quicker. The rest, I'm afraid, is perseverance, but don't dip into your wallets yet, that's for sure.