Rationale:　Photothermal　therapy　(PTT)　alone　is　easy　to　cause　cancer　recurrence　and　fail　to　completely　resist　metastasis,　yet　recurrence　and　metastasis　are　two　major　difficulties　in　cancer　treatment.　Titanium　disulfide　(TiS2)　nanosheet　anchored　iron　oxide　nanoparticles　(IO　NPs)　with　strong　absorption　in　the　second　near-infrared　(NIR-II)　window　and　excellent　magnetic　properties　is　developed　as　therapeutic　agent　for　NIR-II　photoacoustic　(PA)　imaging　and　magnetic　resonance　(MR)　imaging　guided　NIR-II　PTT　triggered　immunotherapy.　Methods:　The　TiS2　nanosheets　were　prepared　through　a　modified　colloidal　chemistry　approach,　and　TSIO　nanoagents　were　prepared　by　using　a　one　pot　self-assembly　technique.　The　magnetic　targeting　capability　of　TSIO　nanoagents　were　monitored　by　NIR-II　PA,　MR　and　thermal　imaging　in　vivo.　The　NIR-II　PTT　combined　with　immunotherapy　effect　was　investigated　in　mouse　breast　cancer　tumor-bearing　mice.　Results:　The　TSIO　nanoplatform　showed　enhanced　tumor　accumulation　when　a　magnetic　field　was　applied　and　had　the　ability　to　real　time　monitor　the　treatment　process　via　dual　NIR-II　PA　and　MR　imaging.　In　addition,　the　magnetic　targeted　NIR-II　PA/MR　imaging　guided　PTT　provides　an　effective　way　to　reverse　the　immunosuppression　inside　a　tumor　and　to　cooperate　with　immunotherapy　to　improve　therapeutic　outcome　of　the　primary,　distal　and　metastatic　tumors.　©　The　author(s).　This　is　an　open　access　article　distributed　under　the　terms　of　the　Creative　Commons　Attribution　License　(https://creativecommons.org/licenses/by/4.0/).　See　http://ivyspring.com/terms　for　full　terms　and　conditions.