Is there any hadith that says that if a person dies in ramadan he will enter Jannah without question answer session and he will enter Jannah for sure?
Although there is no legitimate or weak hadith that specifically discusses the virtue of dying in Ramadan, there is a hadith in Musnad Ahmad that cites the virtue for those who depart this world while fasting, whether in Ramadan or any other month. According to Hudhayfah, Allah's Messenger (saws) said:
“Whoever says La Ilaaha illallaah, seeking the pleasure of Allah and happens to pass away in that state, he will enter paradise. Whoever fasts a day seeking the pleasure of Allah and happens to pass away in that state, he will enter paradise, Whoever gives charity seeking the pleasure of Allaah and that was his final action will enter Paradise.”
There is no specific virtue of entering Paradise without being questioned mentioned in the preceding hadith. Many other hadiths exist in which the Prophet (saws) discusses various activities that Muslims must undertake in order to join Paradise.
This signifies that if a person performs righteous deeds and this specific deed, such as fasting, was his final deed, he will be admitted to Paradise by Allah's kindness, not only because he died during Ramadan.