Abstract: Provided are methods involving the use of biomarkers, in relation to photoimmunotherapy, such as photoimmunotherapy induced by activation of a phthalocyanine dye conjugated to a targeting molecule that binds a protein on tumor cell, for example, an IR700-antibody conjugate, and combination therapies, for example, that include photoimmunotherapy and an additional therapeutic agent, such as an immune modulating agent. In some aspects, the provided embodiments can be used to identify or select subjects for photoimmunotherapy and/or the combination therapy, or to assess the likelihood of response to photoimmunotherapy and/or to the additional therapeutic agents. Features of the methods and uses provide various advantages, such as improved efficacy. In some aspects, the provided embodiments can be used to provide personalized medicine and tailored therapy regimens for subjects.