RecruitingBehavioural interventionDigital CBT for Insomnia and DepressionThis study has two primary objectives, each of which addresses critical clinical and research gaps for individuals who have co-occurring insomnia and depression. The first objective is to address whether sequential treatment of insomnia and depression is superior to a single treatment for either depression or for insomnia, and if so, which treatment sequence is optimal. The second objective is to determine if there are heterogeneity of treatment effects; that is, variation in which interventions are best for which individuals, and if so, to develop and individualized intervention rule to better match individuals with the treatment that is most likely to lead to the best outcomes. A large randomized trial will be conducted to meet these objectives.