Battle of the Camel? I think she shared leadership with 2 other men and lost the battle; regardless, she is very much an exception to the rule as a Mother of the Believers

And although ahadith should not be taken in isolation,

"لَنْ يُفْلِحَ قَوْمٌ وَلَّوْا أَمْرَهُمُ امْرَأَةً ‏"‏‏

During the battle of Al-Jamal, Allah benefited me with a Word (I heard from the Prophet). When the Prophet heard the news that the people of the Persia had made the daughter of Khosrau their Queen (ruler), he said, "Never will succeed such a nation as makes a woman their ruler."

Sahih al-Bukhari 7099

Historically, we see female leaders not having good results