From the scientific argumentation a zombie is a person who is supposed to be dead and has been reanimated by witchcraft through some kind of spell in order to dominate his will, the zombie figure has been used in cinematography to recreate apocalyptic fiction characters.
At the cinematic level, zombies are reanimated corpses in constant organic decomposition with no intelligence, this figure according to the central script of the film is used as slave characters or as creepy undead that hunt humans.
Fig. 2 From the cinematographic point of view, zombies are reanimated corpses in constant organic decomposition with zero intelligence. Image of public domain, Author: Ahmadreza89, 2016
Now, although the figure of the zombie usually occurs within a science fiction environment, from the scientific point of view, mainly at the genetic level, there are "zombie genes" that are activated only after death.
It is known that the death of any organism does not necessarily mean the death of the cells that form it, in the case of us humans, the heart can continue beating in a deceased person, this is not a paradox because for science it has implications related to certain biological activities.
Recent research, the results of which have been published in Scientific Reports, has focused on elucidating what happens to human brain cells after death, since the cells do not die immediately, and therefore remain alive with strong biological activity.
Fig. 3 So-called "zombie genes" and have the ability to activate glial cells, which are involved in inflammation and defense of the nervous system. Image of public domain, Author: NinaMarie, 2010
The genes found in cells that do not die immediately have been called "zombie genes" and have the ability to activate glial cells, involved in inflammation and defense of the nervous system, hence the inference that these glial cells grow in an uncontrolled manner, seeking to collect nearby debris in order to survive a little longer.
BIBLIOGRAPHICAL REFERENCES CONSULTED:
 Dachet F.,, Brown J., Valyi-Nagy T., Narayan K Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain. Scientific Reports. 2021: 11; 6078. Article: Online access
 Parmet S ‘Zombie’ genes? Research shows some genes come to life in the brain after death. 2021. Article: Online access