K-Basket, Avelumab, Biomarker-driven, Advanced Solid Tumor

Inclusion Criteria: * Provided written informed consent for treatment. * Age ≥ 20 years old * Meet at least one of the following requirements; A. PD-L1 positive by IHC or B. EBV positive by ISH or C. MSI-H by IHC or D. POLE mutation E. POLD1 mutation * Progressive disease who failed to previous standard treatment * At least one measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 on time of patient's allocation. * Adequate organ function as defined by the following criteria: A. Adequate hematological function defined by absolute neutrophil count (ANC) ≥ 1500/mm3, platelet count ≥ 100,000/mm3 , hemoglobin ≥ 9.0 g/dL B. Adequate hepatic function defined by AST and ALT levels ≤ 2.5 × upper limit of normal (ULN) and total bilirubin level ≤ 1.5 × ULN C. Adequate renal function defined by and estimated creatinine clearance (CrCl) ≥ 30 mL/min (MDRD) * A life expectancy of at least 90 days * Negative serum pregnancy test at screening for women of childbearing potential * Highly effective contraception for both male and female subjects if the risk of conception exists. Exclusion Criteria: * Previous treatment with immune checkpoint inhibitor (Anti-PD1, Anti-PDL1, Anti-CTLA4 etc.) * Known severe hypersensitivity reactions to monoclonal antibodies (Grade ≥ 3 NCI CTCAE v 4.03), any history of anaphylaxis, or uncontrolled asthma (that is, 3 or more features of partially controlled asthma) * Prior organ transplantation, including allogeneic stem cell transplantation * Significant acute or chronic infections * Active autoimmune disease that might deteriorate when receiving an immunostimulatory agent: * All subjects with brain metastases, except those meeting the following criteria: * Subjects with clinically significant (i.e., active) cardiovascular medical history: cerebral vascular accident/stroke (\< 6 months prior to enrollment), myocardial infarction (\< 6 months prior to enrollment), unstable angina, congestive heart failure (≥ New York Heart Association Classification Class II), or serious cardiac arrhythmia requiring medication * Unresolved toxicity of Grade \>1 attributed to any prior therapies (excluding alopecia, skin pigmentation and anemia). * Pregnancy or lactation * Interstitial lung disease * Known alcohol or drug abuse * All other significant diseases (for example, inflammatory bowel disease, uncontrolled asthma), which, in the opinion of the Investigator, might impair the subject's tolerance of trial treatment * Any psychiatric condition that would prohibit the understanding or rendering of informed consent * Vaccination within 4 weeks of the first dose of avelumab and while on trial is prohibited except for administration of inactivated vaccines