Palliative care integrated with standard oncology treatment improves symptoms, quality of life and communication, and may extend survival in select populations. However, its integration into routine oncology practice remains inconsistent, delayed and unequal. This review critically approaches international guidelines on integrating palliative care into oncology, outlines critical gaps in referral timing, triggers, team composition, haematologic malignancies and resource stratification, and translates recommendations into practical service-delivery models and implementation strategies. Meta-analyses, randomised controlled trials and guidelines collectively advocate for early, concurrent palliative care, delivered by interdisciplinary teams with primary palliative care skills within oncology. However, key gaps persist in referral triggers, service standards, resource-stratified pathways and performance metrics, particularly for haematologic malignancies, caregivers and underserved populations. Crucially, we detail how workforce shortages, inequitable opioid access and financing gaps create predictable disparities for paediatric, rural, low-income and minority populations, and propose practical, resource-stratified adaptations for each barrier. Real-world programmes show promise in multiple delivery models, but scaling these models is limited by workforce shortages, funding, opioid access and infrastructure. This work additionally synthesises evidence on the integration of palliative care in oncology care across different continents and countries. The focus now must shift from demonstrating palliative care’s benefits to ensuring equitable, timely delivery through clear referral triggers, strengthened primary palliative care, sustainable funding and measurable quality indicators.