The Witcher 3 features a classic RPG character leveling system. By performing various actions within the game, the character gains experience points (EXP) and levels up. Theoretically, Geralt's level can be increased indefinitely, but the game has a "soft cap" related to the amount of experience points earned. 

The thing is, as the character develops, the experience gained from killing enemies decreases. And when the player completes all the main and side quests, explores all places of power, and defeats all possible bosses, gaining new levels becomes nearly impossible. This cap is reached at approximately level 60. Of course, spending hundreds of hours to earn points for leveling up can allow players to exceed 60 levels, but it's not very efficient.

This described limitation only applies to the base game. If we consider the expansions "Hearts of Stone" and "Blood and Wine," the maximum level before the soft cap is raised to 70. Players can also start a new game+, in which the leveling process is slightly expanded. Taking into account all these additional factors, a player can reach level 100, beyond which earning a normal amount of EXP becomes impossible.