Meaning
Supreme God Krishna spoke
The three Modes of Nature (Sattva, Rajas, and Tamas) are there as doers behind all actions, but the one who is besieged by ego thinks themselves to be the doer. (3:27)
Sanskrit
श्रीभगवान् उवाच
प्रकृतेः क्रियमाणानि गुणैः कर्माणि सर्वशः ।
अहंकारविमूढात्मा कर्ताहमिति मन्यते॥
Word-by-word
प्रकृतेः क्रियमाणानि गुणैः कर्माणि सर्वशः।
अहङ्कार-विमूढ-आत्मा कर्ता अहम् इति मन्यते।।
Commentary
It might appear from this verse that no Freedom of Will is available to humans, but this is not true. Each verse must be seen in conjunction with other verses relevant to the subject, e.g., 2:47; 5:14, 15; 6:5,6; 18:61,63 in this case. This verse only sets the limits on human freedom. Genetics and environment - nature and nurture - both determine, among others, our actions and decisions to a considerable extent. However, it appears to the ignorant that he is deciding and acting completely independently. Yet, within the framework of genetics and environment, Freedom of Will does exist.