I learned in history class that Hitler was known to cover up his ancestry because he was afraid that his own party would find out that Hitler might of had Jewish ancestry due to his grandma allegedly having an affair with a Jewish man because it’s documented that she didn’t want to reveal who the father was for unknown reasons. The man was allegedly Leopold Frankenberger according to ex nazi Hans Frank?
There's not enough accurate evidence to say that Hitler was Jewish; However, research conducted by journalist Jean-Paul Mulders, and Historian Marc Vermeeren, suggests that there was a significant possibility that Hitler was of Jewish and African descent.
History Stories, August 26, 2010, Jennie Cohen
To unravel the mystery of the Fuhrer’s roots, the Belgian journalist Jean-Paul Mulders teamed up with Marc Vermeeren, a historian who has written extensively about Hitler and his ancestors. The duo collected saliva samples from 39 of the infamous dictator’s living relatives, including a great-nephew, Alexander Stuart-Houston, who lives in New York, and an Austrian cousin identified only as “Norbert H.” Tests were then conducted to reveal the samples’ principal haplogroups, which are sets of chromosomes that geneticists use to define specific populations.Writing in the Flemish-language magazine Knack, Mulders reported that the relatives’ most dominant haplogroup, known as E1b1b, is rare in Western Europeans but common among North Africans, and particularly the Berber tribes of Morocco, Algeria, Libya and Tunisia. It is also one of the major founding lineages of the Jewish population, present in 18 to 20 percent of Ashkenazi Jews and 8.6 to 30 percent of Sephardic Jews. In other words, Hitler’s family tree may have included Jewish and African ancestors.
Edit: Grammar.
Not to discourage further answers, but you might be interested in this previous one by u/Georgy_K_Zhukov.