Study of DT-7012 as a Single Agent and in Combination With an Immune Checkpoint Inhibitor in Participants With Advanced Solid Tumors

Inclusion Criteria: * Histologically or cytologically confirmed solid tumor, among selected cancer types, that is recurrent, locally advanced (i.e., not eligible for curative surgery or radiotherapy) or metastatic, has progressed after at least one line of systemic therapy and has no established curative option. * Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 as assessed by the local site investigator/radiologist. * At least 1 tumour lesion accessible to biopsy per treating physician judgement. * Eastern Cooperative Oncology Group (ECOG) PS of 0 or 1. * Adequate organ function. Exclusion Criteria: * Any unresolved AEs from previous anti-cancer therapies of grade ≥2, with the exception of alopecia. * Prior severe immune-related AEs (irAEs) leading to immunotherapy treatment discontinuation. * Major surgery or significant traumatic injury within 4 weeks prior to Cycle 1 Day 1 with unadequately recovered AEs and/or complications from the intervention prior to Cycle 1 Day 1. * Prior radiotherapy within the 4 weeks prior to Cycle 1 Day 1 or limited field palliative radiotherapy within 2 weeks prior to Cycle 1 Day 1. * Prior anti-CCR8 monoclonal antibody treatment received in an investigational trial