Moksha — release from the cycle of samsara — is the ultimate horizon of every path the Gita describes. Karma Yoga, Bhakti, Jnana, and Dhyana are not ends in themselves; they are ways of arriving at the same summit. Chapter 18, appropriately named Moksha Sanyasa Yoga (the yoga of liberation through renunciation), collects the whole teaching and offers it back to Arjuna as an integrated whole.
The Gita's account of liberation is distinctive on three counts. First, it is available in this life, not only after death — the sthita-prajna of 2.55-72 is a person whose liberation is present, embodied, and observable. Second, it does not require withdrawal from the world; a householder immersed in duty can reach it as surely as a forest ascetic, provided the inner attitude is right. Third, its consummation is described in unmistakably devotional terms — the liberated one 'enters into Me' (18.55), and the passage from the world of becoming to the world of being is finally a passage into the presence of the Beloved.
Read these verses to trace the arc: from the negative description of the liberated mind (unshaken by pain, unelated by pleasure), through the disciplines that produce it, to the positive vision of the soul who has come home.