The laws of retribution in Islam

The following ayah says you could kill whoever killed you type of thing. But I am confused since if a man killed your wife you can kill the man, right? But then what does it mean by a female for female? > يَا أَيُّهَا الَّذِينَ آمَنُوا كُتِبَ عَلَيْكُمُ الْقِصَاصُ فِي > الْقَتْلَى ۖ الْحُرُّ بِالْحُرِّ وَالْعَبْدُ بِالْعَبْدِ وَالْأُنْثَىٰ > بِالْأُنْثَىٰ ۚ فَمَنْ عُفِيَ لَهُ مِنْ أَخِيهِ شَيْءٌ فَاتِّبَاعٌ > بِالْمَعْرُوفِ وَأَدَاءٌ إِلَيْهِ بِإِحْسَانٍ ۗ ذَٰلِكَ تَخْفِيفٌ مِنْ > رَبِّكُمْ وَرَحْمَةٌ ۗ فَمَنِ اعْتَدَىٰ بَعْدَ ذَٰلِكَ فَلَهُ عَذَابٌ > أَلِيمٌ > > • Dr. Mustafa Khattab: O believers! ˹The law of˺ retaliation is set > for you in cases of murder—a free man for a free man, a slave for a > slave, and a female for a female. But if the offender is pardoned by > the victim’s guardian, then blood-money should be decided fairly and > payment should be made courteously. This is a concession and a mercy > from your Lord. But whoever transgresses after that will suffer a > painful punishment. 2:178