Radiotherapy has historically been considered as local anticancer therapy that mainly increases local control rates of malignant tumours and thereby diminishes development of distant metastasis. However, growing evidence shows that radiotherapy is also involved in activation of systemic antitumour immunity. According to the current knowledge, a concomitant combination of immunotherapy and radiotherapy may be one of the most important steps to further improve treatment efficacy in the case of solid tumours. Taking into account all available preclinical information, published case reports and retrospective analyses as well as numerous completed and ongoing clinical trials, we can conclude that combination of immunotherapy and radiotherapy is a new effective treatment modality in oncology. Despite its initial success, further studies are needed to optimize treatment sequences and to find out the best fractionation schedules of radiotherapy.