Background: PARP inhibitors or chemotherapy combined with PD1/PDL1 inhibitors resulting in enhanced antitumor activity. We previously reported the part 1 result of a phase Ⅰb study exploring the safety and efficacy of Cis plus Sint and Nir. Here we presented the updated survival and safety data. Methods: Eligible pts will receive Sint and Cis on D1, plus Nir on D1-21, every 21-day for up to 4 cycles, following Sint and Nir until disease progression or intolerable toxicity. Part 1 was dose escalation phase followed 3+3 model, and part 2 was dose expansion phase enrolled more patients based on part 1. The primary objective was to determine maximum tolerated dose (MTD)/ recommended part 2 dose (RP2D). Secondary endpoints include objective response rate (ORR) per RECIST v1.1, and safety based on CTCAE v5.0. Results: PR2D of Cis and Nir were 60 mg/m² and 100 mg, respectively when combined with sint 200mg. From 7/2019 to 9/2021, 22 pts (13 pts in part2) were enrolled, including 12 small cell lung cancer (SCLC), 7 lung squamous cell carcinoma (LUSC), 2 ovarian cancer (OC) and 1 cervical squamous cell carcinoma (CSCC). Most were male (77.3%, n=17), ECOG=1 (63.6%, n=14), current smoker(68.2%, n=15) and PDL1＜1(50%, n=11). 36.4% (8/22) and 27.3% (6/22) had brain and liver metastasis at baseline, separately. Median follow-up was 6.2 months (range 2.5-10.8). ORR was 27.3% (6/22), DCR was 59.1% (13/22). Median progression-free survival (PFS) was 3.3 months (95%CI 1.9-3.9), and PFS rates at 6 months and 12 months were 28.8% and 10.8%. Median overall survival (OS) was 8.0 months (95%CI 4.9-14.1), 12 months OS rates was 28.5%. Median treatment duration was 4.7 months (range 1.9-15.1). The most common treatment-related adverse events included anemia (90.9%, 20/22, [5 Grade 3/4]), fatigue (77.3%, 17/22, [1 Grade 3/4), γ-glutamyl transpeptidase increased (72.7%, 16/22, [0 Grade 3/4]), leukopenia (68.2%, n=15, [4 Grade 3/4]) and neutropenia (59.1%, n=13, [5 Grade 3/4]). Conclusions: In this updated analysis, Cis combined with Sint and Nir showed clinically meaningful efficacy and an adequate safety profile in previously treated advanced solid tumors. Data need longer follow-up. Clinical trial information: ChiCTR1900024488.