In the Zombie Apocalypse, the System Wants Me to Cultivate Immortality?

[Doomsday Survival + Immortal Cultivation System + Monster Fighting Upgrade + Not the Holy Mother] He Fan, who comes from a low-income family, prepares to use his own efforts to stand out in the college entrance examination, but the people around him suddenly mutate and become "zombie". At this moment, he accidentally awakens the "immortal cultivation system", which can gain experience points by killing different levels of alien zombies to achieve the purpose of increasing his cultivation level. "I, Hefan, will definitely lead mankind to victory!"