Losing items after character's death is one of the greatest difficulties in Escape from Tarkov. Every death during a raid (except for offline raids) causes the loss of the equipment you took with you. However, there are a few ways to keep your equipment or reduce the chance of losing some items after death - we described them on this page of our guide.
One hundred percent guarantee is provided by secure containers like Alpha, Beta or Gamma Container - you will not lose your items in a secure container even after the death of your character. You will receive one secure container at the beginning of the game. Its capacity will depend on the edition of the game you bought, but you can buy better containers from other players in Flea Market.
You cannot hide weapons or armor in secure containers, but you can store ammunition, cash, grenades or items required to complete the mission. This way, even after a failed raid, you can earn some money or complete a quest for NPCs.
If you are wondering how to get one of the best secure containers in Escape from Tarkov, check the separate page of our guide - "How to get a Gamma Container?".
The second way is to insure the equipment - you can do it before the start of the raid (and for an appropriate fee). The insurance provides a chance to return the item after death. For example, you insure your favorite rifle and die during a raid. If the player who took your rifle does not survive the raid as well, your weapon will return to the inventory after some time.