Digital receivers are required to recover the transmitted symbols from their observed channel output.In multiuser multiple-input multiple-output (MIMO) setups, where multiple symbols are simultaneously transmitted, accurate symbol detection is challenging. A family of algorithms capable of reliably recovering multiple symbols is based on interference cancellation. However, these methods assume that the channel is linear, a model which does not reflect many relevant channels, as well as require accurate channel state information (CSI), which may not be available. In this work we propose a multiuser MIMO receiver which learns to jointly detect in a data-driven fashion, without assuming a specific channel model or requiring CSI. In particular, we propose a data-driven implementation of the iterative soft interference cancellation (SIC) algorithm which we refer to as DeepSIC. The resulting symbol detector is based on integrating dedicated machine-learning (ML) methods into the iterative SIC algorithm. DeepSIC learns to carry out joint detection from a limited set of training samples without requiring the channel to be linear and its parameters to be known. Our numerical evaluations demonstrate that for linear channels with full CSI, DeepSIC approaches the performance of iterative SIC, which is comparable to the optimal performance, and outperforms previously proposed ML-based MIMO receivers. Furthermore, in the presence of CSI uncertainty, DeepSIC significantly outperforms model-based approaches. Finally, we show that DeepSIC accurately detects symbols in non-linear channels, where conventional iterative SIC fails even when accurate CSI is available.Such scenarios, referred to as multiuser multiple-input multiple-output (MIMO) networks, are typically encountered in uplink cellular systems, where the number of transmitters as well as receiver antennas can be very large, as in, e.g., massive MIMO communications [2].One of the main challenges in multiuser MIMO systems is symbol detection, namely, the recovery of the multiple transmitted symbols at the receiver. Conventional detection algorithms, such as those based on the maximum a-posteriori probability (MAP) rule which jointly recovers all the symbols simultaneously, become infeasible as the number of symbols grows. Alternatively, low complexity separate detection, in which each symbol is recovered individually while treating the rest of the symbols, i.e., the interference, as noise, is strictly sub-optimal [3, Ch. 6], and thus results in degraded throughput [4]. An attractive approach, both in terms of complexity and in performance, is interference cancellation [5]. This family of detection algorithms implement separate decoding, either successively or in parallel, and uses the estimates to facilitate the recovery of the remaining symbols, essentially trading complexity for decoding delay. While these methods are prone to error propagation, its effect can be dramatically mitigated by using soft symbol estimates [6]-[8], achieving near MAP performance with controllabl...