early captain marvel 25-33 - the first storyline where thanos acquired the cosmic cube
https://marvel.fandom.com/wiki/Thanos_War
after this , his next big tale was one where he teamed up with warlock against warlock's doppleganger , the magnus. he's a bit of a hero in this one.
but after this act of heroism , he reverted back to evil overlord and the issues to get marvel two in one annual 2 and avengers annual 7 - the death of thanos as well as warlock, gamora and pip.
and after his death , his last appearance was in the death of captain marvel as a messanger of death to bring mar-vell to death's realm.