No matter which platform you play on, you're bound to find or be the kind of player to look at hardware for a competitive edge. Whether it's high refresh rate monitors for PC or third-party controllers on consoles, actively measuring your KD (kill/death) ratio is key. But in the case of Destiny 2, you can't see it.
Attracting millions of players each year, the first-person shooter genre isn't going anywhere. With all those players, there's a bunch of PvP firefights breaking, leading to a very large group of people concerned about whether they're killing more than they're being killed.
Thankfully, Bungie's servers do actually keep track of such statistics - to a degree. Though they're not publically viewable in-game for whatever reason, many of the tools originally used to keep tabs on a player's KD ratio in the original Destiny have been updated to work with the recently released Destiny 2.
By using sites like DestinyKD or DestinyTracker you'll be able to view a fairly detailed analysis of your stats - like Crucible KDs. While not pinpoint accurate due to data and tracker limitations, it's enough to give you a sense of your playstyle.
If you're looking at a fairly negative KD ratio, it may be time to think about your strategy. Most players have adopted the tried and tested Call of Duty run n' gun method into every other FPS title they play. Learn to pick your battles and know when (and how) to retreat. A death is wasted time.