Study to Assess EXS21546 in Combination in Patients With Advanced Solid Tumours

Inclusion Criteria: * Aged ≥ 18 years at time of informed consent. * Previous histologically confirmed diagnosis of RCC or NSCLC having received previously checkpoint inhibitors as part of a SoC regimen. * Consent to mandatory paired tumour biopsies of at least one tumour site accessible for repeat biopsies. Planned sites for tumour biopsies must not have been previously irradiated and could be a target lesion of \>2 cm diameter according to RECIST v1.1 and must be approved on a case-by-case basis by the Sponsor. * Measurable disease as per RECIST v1.1 and documented by computed tomography (CT) and/or magnetic resonance imaging (MRI). Exclusion Criteria: * Any anti-tumour therapy, including investigational therapies, within 4 weeks prior to the first dose of EXS21546. * Unresolved or unstable serious toxic side-effects of prior chemotherapy or radiotherapy, i.e., ≥ Grade 2 per CTCAE v5.0. * Concurrent other malignancy that could interfere with response evaluation. * Symptomatic central nervous system (CNS) malignancy or metastases. Screening of symptomatic participants without history of CNS metastases is not required. Participants with asymptomatic CNS lesions should have completed standard therapy for their CNS lesions 60 days prior to study enrolment. * History of interstitial lung disease and/or prior immunotherapy-related pneumonitis. * Patients who have had or are scheduled to have major surgery \< 28 days prior to the first dose of study drug.