A Study of ARGX-110 in Participants With Advanced Malignancies

Inclusion Criteria:

* Histological diagnosis of malignancy refractory to, or relapsing after standard therapy
* Solid tumors or T-cell malignancies positive for the CD70 antigen by Immunohistochemistry/Fluorescence-activated cell sorting (IHC/FACS) within 56 days prior to administering the first dose of ARGX-110. IHC criterion: greater than \> 10 percent (%) of CD70 positive tumor cells
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, or 2
* Serum albumin greater than or equal to (\>=) 20 gram per liter (g/L) (solid tumor only)
* Ability to comply with protocol-specified procedures/evaluations and scheduled visits. In particular, the ability of the patient to undergo a tumor biopsy (optional for safety expansion cohort 4)

Exclusion Criteria:

* History or clinical evidence of neoplastic central nervous system (CNS) involvement
* History of another primary malignancy that has not been in remission for at least 1 year
* Systemic glucocorticoid administration at doses greater than physiological replacement (prednisolone 20 milligram \[mg\] equivalent) within 28 days of ARGX-110 first dose administration (for T-cell malignancies higher systemic dose can be allowed following discussion with Sponsor)
* Major surgery within 28 days of ARGX-110 first dose administration
* Unresolved grade 3 or 4 toxicity from prior therapy, including experimental therapy