Inclusion Criteria:  Pathologically or cytologically confirmed advanced melanoma or urothelial carcinoma that failed, couldn't tolerate or refused standard treatments ECOG score 0 or 1; Part B: At least 1 measurable lesion according to RECIST 1.1  Exclusion Criteria:  Known hypersensitivity to any ingredient of TWP-101; Receiving any anti-cancer drugs; History of serious systemic diseases; History of serious autoimmune diseases; Pregnancy or lactating women.