To improve the efficacy of traditional chemotherapy and radiotherapy and reduce their serious side effects, further efforts need to be exerted to identify better cancer therapeutic options that are effective, affordable, and acceptable to patients. In this study, a novel theranostic agent was produced to perform synergetic cancer immunotherapy and phototherapy. The theranostic agent, named natural killer (NK) cells carrying indocyanine green loaded liposomes was synthesized NK cells with ICG nanoparticles to serve as the agent for a newly-established cancer treatment. It is expected that the developed synergistic therapy can pave a new avenue for improved efficacy of cancer theranostics.