At a certain point in the main game in Rise of the Tomb Raider, you will stumble upon a fully-sized bear. A lot of players have reported some issues with killing this, but if that's the case with you, then you are in the right place, because we got a guide on how to kill the bear in Rise of the Tomb Raider very easily.
Start off by eliminating all the Trinity Soldiers outside the cave. When you enter the bear cave, do it very slowly. You want to approach the bear from as far away as you can, so stop when you can see it.
Begin the fight by shooting a Poison Arrow at it. Now quickly fire three regular arrows at it, and at this point it will begin to run towards you. Once again shoot it with a Poison arrow to momentarily stun it. This gives you time to fire another three arrows directly towards it, dealing a lot of damage while the bear is incapacitated.
Unless you miss any of the shots, the bear should be dead by now. However, a lot of people miss a shot or two, so just keep firing regular arrows if it's still standing. If you think you missed three or more shots, fire another Poison Arrow first to keep it stunned for a little while longer, or just try again.
And congrats on killing the bear in Rise of the Tomb Raider! Make sure to loot the pelt before you keep progressing further, since it's great to have for later use.