ESID 2026 is a four-day international immunodeficiency meeting for clinicians, scientists, nurses, patient advocates and trainees working with primary immunodeficiencies, secondary immunodeficiencies and inborn errors of immunity. The programme theme is Translational Immunology Beyond Boundaries, with plenary sessions on immune metabolism, pathway dissection, host-pathogen interaction, thymus biology and AI in IEI care, plus parallel sessions, meet-the-expert teaching, working party meetings, poster walks and e-poster discussions.\n\nFor trainees and early-career doctors, the meeting has a strong research route. Late-breaking abstracts are open until 30 August 2026 and may be submitted for oral presentation or poster viewing; abstracts require results, a 25-word title and 250-word structured text. Accepted abstracts from registered participants will be published in The Journal of Human Immunity. ESID Juniors activity includes an Education Day session, a Juniors Working Party session and a networking event. Registration is available for in-person and virtual attendance, with reduced ESID Junior rates and a regular-rate saving deadline of 21 September 2026. CME/CPD accreditation is being sought through UEMS-EACCME; final credit points were not published when scraped.